The German Blitzkrieg underway. A German self-propelled gun is pictured on the move through Cambrai during the invasion of France and the Low Countries in 1940. According to the original album the image was taken from, the unit is Panzerjäger SFL Pz.Jg. I. (Historic Military Press)

Throughout 1940 and 1941 building of anti-invasion defences continued apace throughout the UK. ‘Concrete barriers are ready on the roads, blockhouses have been built, barbed wire barricades are waiting’ notes the original caption to this picture, dated 22 August 1940, of a soldier on duty by a pillbox. (Historic Military Press)

A camouflaged defensive position constructed in the north wall of Pevensey Castle, East Sussex, during the Second World War. One report states: ‘At the time of the construction of the defence works in the walls of Pevensey Castle, from late July 1940 through August and September, the infantry regiment at Pevensey had been the 4th Bn. Duke of Cornwall’s Light Infantry, and the commander of this battalion, Lt. Col. Harrowing, appears to have been responsible for the siting of the machine gun emplacements, and for organising the strengthening of various of the dungeons and towers of the medieval castle to serve as headquarters buildings. This work was carried out by 562nd Field Company Royal Engineers.’ (Historic Military Press)

Soldiers from the Royal Scots lay barbed wire defences during the summer of 1940. (Historic Military Press)

The British Army on exercise during 1940. Here we can see a Morris Commercial CDSW 6x4 Field Artillery Tractor towing an 18/25-pounder on a Mk.1 Carriage. The sheer scale of the losses of both men and equipment during the fall of France and the subsequent evacuation from Dunkirk meant that, in the summer of 1940, the British Army was frequently lacking in artillery pieces such as these. (Historic Military Press)

Members of the Home Guard manning an improvised road block in the summer of 1940. (Historic Military Press)

Throughout the summer of 1940, the British Army watched and waited for any sign of the invasion. (Historic Military Press)

A picture of the flame barrage demonstration held in (or on) the waters of Studland Bay, Dorset, on 1 February 1941. As the patches of oil on the surface of the sea merge into one another to form a continuous strip, the strip is ignited at several points, and the oil begins to burn.(Historic Military Press)

Members of the 1st Northumberland (Berwick) Battalion, Home Guard, the so-called ‘Fishermen’s Home Guard’, take ‘a wellwarned rest during a Sunday morning’s manoeuvres on their island home’, 30 June 1942. A handwritten note on the rear states the image was taken at Lindisfarne. Second from the left is Corporal John Tough, a fisherman by profession. (Historic Military Press)

A member of the RAF Regiment at a machine-gun post, part of the defences of an un-named airfield in the UK. (US Library of Congress)

Personnel of the Auxiliary Territorial Service at a heavy anti-aircraft gun site in the UK, February 1943. Note the winter clothing they are wearing. (US Library of Congress)

A photograph of Spitfires of 65 Squadron at RAF Westhampnett between October and December 1941. (Mark Hillier Collection)

RAF personnel raise a balloon barrage during the Second World War. Barrage balloon units played an important part in the UK’s defence against German aircraft and then, later in the war, the flying bomb menace. (Historic Military Press)

The scene in the Aldwych, London, caused by the explosion of a V-1 flying bomb, March 1944. (Historic Military Press)

The moment that a German V-2 rocket is testfired. The first test launch of a V-2 occurred on 13 June 1942. The first V-2 strike against the UK took place on 8 September 1944. (Historic Military Press)

Evidence of Britain’s wartime defences can be seen throughout the country. This pillbox, for example, is located in High Wood near Christ’s Hospital, Horsham, in West Sussex. (Historic Military Press)