The man called Mark walked into the toilets of the Green Man pub shortly before 8.25pm. An audio tape was wired into his sleeves and he had £80 cash in his pocket. He was wearing the paint-flecked overalls of a painter and decorator. Mark found the man he was looking for relieving himself at one of the urinals. His target had short hair and was wearing white trainers and a blue Adidas jacket. Mark walked casually over to the urinals, unzipped his flies and began to pee.

‘Did you want anything tonight?’ the man in the Adidas jacket said. ‘You asked me last week, didn’t you?’

‘Is there anything about?’ Mark replied.

‘Yeah, what do you want?’

‘A little bit of white, say?’

‘What? Charlie?’

Mark confirmed he wanted to buy cocaine. The drug dealer offered him half a gram of the class A drug for £25, warning him that the powder was not the best quality. It was about the going price for half a gram of cocaine picked up in a north London pub in 2001. Mark said he would buy it. Just before handing over the drugs, the dealer paused and scrutinised the talkative customer. He had a wide nose and a wonky left eye.

‘Obviously, you’re not Old Bill?’ the dealer asked.

Mark zipped up his trousers and laughed. ‘Fuck off, mate.’

*

Mark Kennedy was, indeed, Old Bill. He was a police officer with a quite extraordinary future ahead of him. He would go deeper undercover, and take far more risks than either Marco Jacobs or Lynn Watson, or indeed any other spy known to have worked for the National Public Order Intelligence Unit. But his success would lead to his downfall. In just over a decade, his life would unravel with remarkable speed, making him, for a period of time, the most talked-about undercover police officer in the world. ‘He was as deep a swimmer as there ever was,’ says fellow police spy, Pete Black. ‘He was absolutely professional. He was just like Bob Lambert – he lived and breathed the role.’

Given the man he was to become, Kennedy had an inauspicious start to life. He was raised in the commuter-belt town of Orpington, in Kent, the son of a policeman, John. Kennedy and his brother Ian seem to have had a contented upbringing as they grew up in the 1970s, with one notable exception. As a two-year-old, Kennedy stumbled across an empty cardboard box and started playing around with it. A staple came loose and became lodged in his left eye, causing instant and irreparable damage to a muscle. The injury left Kennedy permanently suffering from a strangely appropriate disfigurement for someone who made a living from duplicity: he always looked as though he was glancing in two directions at once.

It was a tough start in life for Kennedy, who soon developed a stammer. He tried to overcome his impediment by speaking in a slow, deliberate way that would later in life lead people to assume he lacked intelligence.

At 16, he left school with few qualifications to his name and took a lowly job as a court usher, before deciding to follow in the footsteps of his father. Years later his father John Kennedy would say he encouraged his son to become a police officer. ‘Being a policeman was a way of life for the family. You’ll never be rich. But you will be proud of what you have done.’

A photograph from 1990 shows a young-looking Mark Kennedy, squinting at the camera from beneath a helmet embossed with his constable number. He had joined the City of London police, a small force that only has jurisdiction over the financial district of London. He settled into the suburbs, moving into a house with his parents and then marrying an Irish retail manager, Edel. The couple had two children, a boy and girl. It was the foundations of the kind of quiet, sedentary life that Kennedy showed every sign of disliking.

He bought himself a motorbike and took up long-distance running. He was an enthusiastic rock climber and started travelling further afield in search of the adrenaline of dangerous climbs, including one expedition to Pakistan. By 1998, Kennedy had transferred to London’s Metropolitan police and begun going undercover briefly to purchase drugs from dealers.

And so it was that in October 2001, a few years before he turned his attentions to spying on protesters, Kennedy found himself walking into the Green Man pub in Barnet in search of cocaine. He was working on Operation Smoothflow, a sting to bring down one of the most notorious places to score drugs in the area. The man in the Adidas jacket who sold Kennedy a wrap of cocaine in the toilets had no idea he was an undercover cop. Kennedy and three other police officers had been drinking in the pub for weeks, posing as manual labourers with wires sewn into their outfits.

When police eventually got round to raiding the pub with sniffer dogs, they arrested a couple of dozen customers and hauled them off to the station. Prosecutors charged 13 people, mostly for supplying small quantities of drugs or for possession. Only one decided to plead not guilty and risk a higher sentence: the man accused of being the drug dealer who gave Kennedy cocaine in the toilets.

From the start, detectives had a problem trying to identify the dealer in the Adidas jacket. When he sold Kennedy drugs, he refused to give him his name or telephone number. There was no DNA or fingerprint evidence on the wraps of cocaine. The audio recordings were so muffled that it was not possible to identify the culprit’s voice. Eventually police decided the guilty man was the pub’s 18-year-old barman, Gary Pedder.

The teenager denied ever having sold drugs to anyone and pointed out there were several other people in the premises wearing Adidas clothes. His mother, Josephine, insisted her son would never deal drugs and said police had the wrong man. Police searched their home but found no evidence of drug paraphernalia or suspicious stashes of cash.

Several months later, Pedder found himself in the dock at Hendon magistrates court. ‘All the way through I said I never did it. It wasn’t me. You’ve got the wrong person,’ he says. It was his word against that of Kennedy, who testified under oath that Pedder was the man who sold him drugs. Pedder says none of the other undercover police officers felt confident enough to finger him as the suspect.

As he was leaving, Kennedy bumped into Pedder outside the courthouse. ‘He walked past me and my mum and my girlfriend,’ Pedder says. ‘He said “sorry” and then just got on his motorbike and drove off. My mum was there and said, “Did he really just say that? Did he just say ‘sorry’?” Everyone was in shock.’

A few hours later, the jury returned its verdict. Pedder was found guilty of five counts of supplying a class A drug. He was sentenced to five years in prison.

Kennedy declined to comment on the Pedder case. However, reflecting on his years purchasing drugs for the police, he once told a journalist: ‘I was a natural at undercover work and I loved it. Drug work was black and white. You identify the bad guys, record and film the evidence, present it in court and take them down. I did that for four years and loved it.’

Kennedy’s enthusiasm for undercover work did not go unnoticed. By the time Pedder began his prison sentence in 2002, the constable who put him behind bars had made an important career move. Kennedy twice asked to transfer to the NPOIU, but initially, for some reason, was considered an unsuitable candidate. On his second application he was accepted and told he would work on Operation Pegasus, the same mission to target left-wing environmental campaigners as Lynn Watson.

He would have to relocate and start a new life in Nottingham, on a salary of £50,000. This new deployment was quite unlike his brief forays into pubs purchasing drugs. His targets were a close-knit group of eco-activists in Nottingham and Kennedy was told he was expected to spend years living among them. They socialised around the Sumac Centre, which contained a vegan fast-food business in the basement. Upstairs, there was a library and space for parties, film screenings and workshops. There was also a bar with a small sound system and a garden out the front growing organic food. It was not unlike the Common Place in Leeds, which Watson helped set up, or Brighton’s Cowley club, where Marco Jacobs made his first, faltering introductions.

Like the other NPOIU spies, Kennedy invented a fictional identity that might make him useful to activists. In some respects he stuck to the usual formula. He too, for example, would tell friends that he was recovering from a messy break-up with his girlfriend and had moved cities to get away from her. He decided he would be a ‘rope access technician’, or professional climber, a job that would allow for a van, and long absences from Nottingham when he could claim to be in distant parts of the country painting cranes or cleaning skyscraper windows. He would also tell friends he did part-time work as a driver, for an uncle named Phil.

But if Kennedy was going to justify his generous expense account, his alias would need another source of funds. He decided to make his fake persona a former criminal who had earned a small fortune smuggling cocaine into Europe from Pakistan. This was not something he would ever announce. Instead it was a secret that would unfurl slowly, providing a second layer to his identity. He could be a risk taker thirsting for excitement, and someone wanting also to seek redemption for past failures.

There were of course threads of truth to this deception. He had travelled to Pakistan, so if he was ever pressed he knew he was familiar enough with the country. His previous undercover work also gave him some grasp of the cocaine trade. All told, it made for a clever ruse. Kennedy could have plenty of cash, and an excuse for not wanting to speak about his past.

Once an undercover police officer has established their legend, the rest was no more than ritual. Kennedy selected a name, settling for two clean syllables: Mark Stone. His surname was ‘just an easy name to remember. It is a popular name. It is not difficult to forget in stressful circumstances.’ He says he spent ‘about a year’ researching neighbourhoods and schools in London, joining Friends Reunited so that he could talk convincingly about his fake background. He was given the codename UCO 133 and introduced to his NPOIU handler, a sergeant called David Hutcheson. Finally he was issued with credit cards, bank accounts and a fake passport and driving licence. Both identity documents had photographs of a podgy-looking Kennedy with cropped hair.

By then, however, Kennedy was morphing into his new identity. He purchased a new wardrobe of mostly black clothes, pierced his ears and let his hair grow. When he looked in the mirror, the glance would have been returned by a stranger. He had the same damaged left eye, but Mark Stone looked completely different to his former self. He now had a gingery beard and shiny long hair.

No one at the Sumac Centre can say exactly when Mark Stone turned up. He just appeared. One day, he was sitting in the Sumac’s vegan café taking part in a letter-writing campaign to call for changes to the prison system. He enquired about a poster hanging on the wall advertising transport to Earth First, an annual gathering of environmentalists. The NPOIU knew this to be a must-attend event in the calendar of many radical green campaigners.

In 2003 it was held on Lime Tree Farm, near the village of Grewelthorpe in North Yorkshire. This was what activists liked to call a ‘safe space’; rescued from its previous life as a dairy farm, the fields had been transformed into a spiritual sanctuary and nature reserve. The organisers of Earth First tried to create a campsite without hierarchy, in harmony with its surroundings, to meet, socialise, debate and plan for the year ahead. There was a communal kitchen, bicycle-powered generator, compost toilets and, for those so inclined, a nude hot tub. ‘It was like a very straight festival,’ says a key Earth First activist. ‘Workshops all day, everyone eats the same vegan food for their meal, cooked by the Anarchist Teapot collective, and a bit of drinking and socialising in the evening, but not an all-night party.’

Central to the workings of the camp was that decisions should be reached by consensus, rather than vote, and the activists used a strange-looking ritual known as ‘jazz hands’, in which they wiggled their fingers in the air to express support for speakers.

One decision reached that year was to target the German biotech company, Bayer, which was entering the global market in genetically modified crops. A few weeks later, Kennedy was taking part in his first direct action protest, driving a people-carrier filled with activists to a small subsidiary of the company in Huddersfield.

It was 5am and the road was empty. Two activists were wearing cartoon stuffed animals on their heads. Another had brought a Chinese jaw harp to play. Activists blocked the road with a large metal tripod, locked themselves to the entrance of the building and handed out leaflets to office workers. Kennedy was getting his first taste of domestic extremism.

If Kennedy was going to burrow deeper, he needed to make friends. The Nottingham Crew, as one group of activists from the city were called, were an older crowd, and many of them had ties stretching back decades. Friendships had been forged in the anti-roads movement in 1990s, made famous by the battles against plans to build a bypass near Newbury. Others had been involved in Reclaim the Streets, and had been around long enough to encounter other police spies, such as Jim Boyling. It was never going to be easy for Kennedy to persuade these strangers to trust him. They were serious activists, and could be suspicious of outsiders.

Kennedy would have been provided with a detailed briefing about the group he was infiltrating. Much of this information is likely to have come from other undercover police. His suspected predecessor in Nottingham was an infiltrator who posed as an activist called Rod Richardson. Named in parliament as a suspected police officer, Richardson turned up in 2000 and disappeared shortly before Kennedy was deployed, claiming to be migrating to Australia. He drove a dark blue Peugeot 505 and claimed to be earning money working as a fitness instructor. He was extremely camera-shy; on one occasion, at the G8 summit in Genoa in 2001, he scratched out his face from a photograph of British activists. In other images from the summit, Richardson’s face is concealed behind a gas mask, as he poses next to a burning car that has been turned upside down. In all other photographs, he appears to be hiding his face. Richardson rented a room in another activist house and painted the walls with bright red sperm he called his ‘worms of doom’.

Kennedy, who was presumably briefed by Richardson about the best way to gain access to activism in Nottingham, chose a similar strategy: renting a spare room at a house near to the Sumac. It was rented by five politically engaged campaigners. Kennedy took a room on the top floor and built himself a four-poster bed from discarded scaffolding. He tried to be the model housemate, washing, cleaning, doing odd jobs around the house. He also made a point of giving his room-mates gifts.

One housemate, the recipient of a T-shirt, says Kennedy was ‘a breath of fresh air’. ‘He was very creative – good with his hands – and he drove around a lot,’ says Loukas Christodolou, then aged 26. ‘It was like he was there to enrich our lives.’ But there was something about Kennedy that made him a little too keen. ‘He was like an Afghan hound with his long hair and puppy eyes. He had this air of extreme vulnerability while also wanting to get stuck in,’ Christodoulou adds. ‘People in the early days called him “dodgy Mark”. He just didn’t seem right.’

It was as though Kennedy’s housemates could see through the mask. ‘Mark Stone looked like a copper,’ says Christodoulou. ‘He was heavy-built, a kind of lower-middle-class man. He had a certain physical readiness about him. I remember people saying: he can’t be a copper, he has a funny eye – he wouldn’t get into the police with dodgy eyesight like that.’ Others around at the time agree that Kennedy initially struggled to fit in. As one friend puts it: ‘Mark needed to prove himself.’

One strategy he used was an NPOIU favourite. One day, Kennedy told his housemates that he had some childhood friends visiting and asked if they could sleep on the sofa. ‘They were both heavily dreadlocked and bearded,’ says Christodoulou. ‘One of them was strawberry blond and had huge amounts of hair – he called himself Ed and he was really jocular. He was just relaxed and joking.’ He says the second man was ‘dark, with a bit of a beaky nose’ and much taller. ‘He was totally silent and seemed scared out of his wits. I just assumed he had taken bad drugs back in the day.’

Both of these friends were almost certainly fellow undercover police officers. Lynn Watson used a similar strategy when she introduced two operatives as her boyfriends. So too did Rod Richardson, who occasionally introduced his friends to a woman called ‘Jo’ who they now believe must have been a fellow spy. Kennedy of course had no reason to introduce his friends to female undercover police, to pretend they were his girlfriends. Doing so would have been counterproductive.

His alter ego was more in keeping with the template used by the SDS for decades: Mark Stone, as activists knew him, was a bachelor looking for a long-term girlfriend.

Within just four months of his Nottingham deployment, Kennedy had chosen his first woman. Lily was a bright and popular 23-year-old whom he met at a political event in Nottingham. ‘We started hanging out after that meeting,’ she says. ‘He was very charismatic, exciting, good fun. He claimed to like country music, caravans. He claimed to be interested in climbing, in travelling, in all kinds of political projects. He seemed like a really nice guy. He was quite a lot older than me – nearly 10 years older. He was very romantic and set the tone for our relationship.’

Kennedy appears to have had no qualms about getting deep into the life of the young activist. On the frequent occasions they passed through London they stayed at her parents’ flat in Putney. ‘They both had long hair so they would sit down and watch TV, combing each other’s hair after it was washed,’ says her mum, Pauline. ‘He used to eat with us and slob around watching TV with us. All the stuff you do in a relaxed way with people in the family.’ The spy worked hard to gain the affections of his girlfriend’s family. He bonded with her brother over Chelsea football club and when her mother’s choir group sang outside East Putney Tube, Kennedy stood beside them rattling a can for donations. He also accompanied Lily and her mum Pauline on a trip to the theatre, telling them it was the first time he had ever worn a suit.

So close did he become that within just a few weeks of going out with Lily, he found himself at her grandmother’s 90th birthday. There is a photograph of him there, wearing a roll-neck sweater beneath a quilted waistcoat. Pauline said she found her daughter’s new boyfriend ‘quite funny, good company’ but thought he was different to her previous companions. ‘Mark was laddish, compared to some of Lily’s more cerebral friends,’ she says. ‘He was not particularly bright or articulate and didn’t have a hugely broad vocabulary. He talked about politics in a much more naïve, down to earth kind of way.’

Kennedy’s relationship with Lily was profoundly different to the one he had with his Catholic wife in his real life. Lily believed in open relationships, more formally known as polyamory. Proponents of open relationships say that this unconventional approach is no less meaningful than traditional, monogamous partnerships, which can leave people feeling shackled. Open relationships are different with each couple, but often the arrangement allows both people to have more than one sexual partner, which advocates say encourages honesty.

This of course allowed Kennedy to have more than one girlfriend at a time. ‘He was a bit different from all of us. He ate meat, had a pickup truck and was just not very hippy in a way,’ says Anna, a 21-year-old Kennedy slept with around 20 times. ‘I knew he was seeing other people at the same time and it was never, you know, any type of romance involved.’ It is not possible to know exactly how many women Kennedy slept with during his six years undercover. He claims it was only two. His friends in Nottingham can name more than 10 women he slept with while living in the city and expect there were more. ‘It just seemed he was up for sexual liaisons anytime, anyplace, anywhere,’ Christodoulou says. ‘He had just come on board and he was at it right away. One person I know who had a romantic relationship with him challenged him and said: ‘I’m not going any further because I think you’re a copper.’ Then Mark said something to her which apparently calmed her down.’

Not long after Lily’s grandmother’s 90th birthday, the effort Kennedy was putting into his second life was paying off. He was attending various political meetings with her up and down the country. He travelled to a May Day protest in Dublin with an anarchist collective called the ‘White Overalls Movement Building Libertarian Effective Struggles’, or WOMBLES for short. They were famed for their tactic of covering their bodies with white overalls, padding and helmets to protect themselves from riot police, a tactic they anointed ‘self-protection from the depredations of the constabulary’. It was the same group that Richardson had infiltrated just a few years earlier.

Kennedy returned from Ireland boasting that he had been drenched in water cannon and nursing his first protest injury, a damaged knee. It was his first bruising encounter with his colleagues in the riot squad, and Kennedy seemed to have relished it. He cut out a newspaper photograph of himself stood in a line of masked anarchists and hung it framed on his living-room wall. After that, Kennedy delved into a panoply of activist events. ‘It was really a smorgasbord of grievances,’ says a friend. ‘It could have been saving the animals one day, stopping the BNP the next day, protesting against a war in some far-flung corner of the world the next day, and then trying to stop an asylum seeker getting deported or a post office closed. I just assumed he was a bit of a lost soul looking for something he could believe in.’

By the following year, Kennedy had inveigled himself into the core of the group mobilising ahead of the G8 summit in Gleneagles. There was no greater NPOIU priority at the time than gleaning intelligence about how protesters planned to disrupt the meeting of world leaders in July 2005. Kennedy would come to view his surveillance operation at the G8 summit as one of the high watermarks of his entire deployment, and claim his reports were reaching the desk of the then prime minister, Tony Blair.

The anti-summit protests were months in the planning. Blair had suggested the G8 would deliver agreement among leaders on two totemic issues: climate change and economic development in the world’s poorest nations. Protesters were loosely split into two camps. On one side, there was a large and moderate coalition of trade unions, charities and campaign groups that coalesced under the Make Poverty History banner. They planned a huge demonstration through Edinburgh, capitalising on the spirit of the protests against the Iraq war. On the other were the more radical contingent of anti-capitalist protesters, of whom Kennedy was part, mobilising under the name Dissent. Their objective was to stop the G8 summit meeting from taking place by blockading roads to the fortified hotel and other forms of ‘resistance’ to the state.

If they were going to be organised, the protesters needed a base, and they chose to construct an Earth First-style campsite 12 miles from the Gleneagles Hotel. It would be another sustainable camp, host to thousands of protesters from across Europe. Kennedy volunteered – and was considered sufficiently trustworthy – to co-ordinate the immense logistical challenge of ferrying equipment to the camp.

He hired a convoy of vans and began touring the country to pick up ropes, portable toilets, tent poles, canvas and other supplies. He was accompanied by a 22-year-old student from Holland named Wietse van der Werf. ‘Mark was willing to take stuff on,’ he recalls. ‘He seemed keen and took the initiative. People just let him get on with it. If you have someone that has a credit card ready to hire any vehicle, and a political movement that doesn’t have a lot of funds, then that person becomes very valuable, very quickly.’

The Dutchman remembers a laptop placed on the back seat of Kennedy’s pickup truck which was connected remotely to the internet. ‘This was 2005 – that was quite uncommon back then,’ he says. Kennedy often encouraged activists to borrow his laptop to send emails, presumably to spy on their electronic communications. He was also a fast driver, and had some curious routines. It was only years later, and with the benefit of hindsight, that it dawned on Van der Werf that his friend’s driving habits were those of a police officer. ‘He took tea breaks all the time and bought food whenever we stopped,’ he says. ‘He also made a point of keeping all of his receipts.’

In the end, the G8 protests, like the summit they intended to disrupt, did not quite live up to expectations. There were some roads blocked, although never for that long, and an attempt to break through the perimeter fence of the hotel ended when riot police emerged out of Chinook helicopters.

But for Kennedy, the G8 was an impressive milestone. The NPOIU had a whole network of spies at the protests, including both Watson and Jacobs. So too did the SDS, and foreign police spies were invited to attend too. Germany alone sent five undercover police officers. But no infiltrator is believed to have come close to securing the kind of access Kennedy achieved.

He now had a reputation among activists as a reliable and trusted campaigner who could get things done. Just two years after first showing his face in Nottingham’s Sumac Centre, Kennedy had wormed himself into the close-knit group of radical activists and, with the help of Lily, landed himself a key role by taking care of logistics, and a new nickname: Transport Mark. He was no longer being viewed through the prism of suspicion. He was just Mark Stone. And he was on a roll.