The Occupation of Norway, Denmark and Holland
The expected onslaught from the air at the outset of the War did not materialize. The German air striking force had been created not as a weapon for forcing a decision by independent air action, but rather as a means for preparing the way for the rapid advance of an army through enemy territory. Several authorities in this country had believed that an air attack would not be launched until the German army, with which half the German air force had been trained, was ready to exploit a success.
The postponement of air attack throughout the Winter gave the needed time to improve the air defence preparations. The task was interrupted in the Spring (1940) by the opening of the German offensive against the Western Powers. The occupation of Norway and Denmark in April, and the invasion of Holland on the 10th May brought about the critical situation which had long been foreseen, but so inadequately faced, by the Cabinet and the Chiefs of Staff.
The assumptions upon which the Air Defence of Great Britain had been based were transformed. German bombers based on Dutch aerodromes would be able to have fighter escorts over the most vulnerable parts of the country. The Chiefs of Staff admitted, too, that their former assurances on the negligible risks of invasion were no longer valid.
Precautions Against Seaborne and Airborne Landings
Additional precautions were ordered by the Chiefs of Staff within the framework of the Julius Caesar plan. Light naval forces adequate to intercept a seaborne expedition from Dutch harbours were placed in readiness. The East Coast mine-barrage, laid from off Scotland to the Humber to cover possible landing places from German harbours only, was extended southwards to include the Thames estuary; and all East and South-East coast ports from the Wash to Newhaven were prepared for short-term (7 days) immobilisation. Naval brigades were formed as an additional garrison for naval ports and dockyards; and the Coastguard, a civil organisation under the Ministry of Shipping, was taken over by the Admiralty.
Likely airborne landing grounds, such as straight stretches of arterial road and other open spaces within 5 miles of ports, possible landing beaches and air-fields up to 20 miles of the East Coast, from Sunderland to Hastings, were ordered to be obstructed by road-blocks, overhead wires, poles or trenches; all roads leading to ports and coastal aerodromes had blocks placed in position, and bridges in the area were prepared for demolition.
Church bells throughout the country were only to be rung as a warning signal of enemy parachutists or airborne landings; the order to that effect was issued by the Ministry of Home Security on the 13th June after discussion with the Ecclesiastical authorities.
The Local Defence Volunteers (Home Guard)
According to the Julius Caesar plan airborne troops and parachutists who succeeded in landing were to be dealt with by the A.A. gun and searchlight detachments in the network of the Air Defence system. The Observer Corps, watching the greater part of the country was in direct communication with the military authorities in each area. In addition the Police Force, with a peace strength of 60,000, was to be armed, and rifles distributed to the County Police for “Flying Squads” to deal with parachutists.
Those precautions were, however, considered inadequate to meet the increased threat. To ensure that parachutists should be dealt with at once the War Cabinet authorised, on the 13th May, the creation of a Local Defence Volunteer Force. This citizen force, voluntary and unpaid, with part-time duties except in an emergency, was required to deal without delay with an enemy arriving by whatever means in the vicinity of their villages and parishes.
Volunteers soon reached the half a million mark. Enrolment was only restricted by the shortage of rifles; 100,000 old rifles out of the repair shops were available up to the end of May, and to make good the deficiency until the arrival of consignments of rifles ordered from Canada and the United States, civilians were asked to hand over any shot-guns in their possession.
The Home Defence Executive
Anti-invasion schemes by civil departments and local authorities, considered unnecessary before the war, had to be extemporised. Voluntary evacuation from East and South coast towns was encouraged; but if invasion occurred the population throughout the country were to stay where they were, and keep of the roads, particularly in coastal areas. The coastward roads would be required for military movements, and would be subject to deliberate air attack by German bombers. In view of possible Fifth Column activities and sabotage with 73,000 aliens at large in the country, all enemy aliens and members of subversive organizations were rounded up and interned.
To avoid assistance to airborne or seaborne troops railways were prepared for immediate immobilization; and the Ministry of Transport undertook the removal of signposts and milestones throughout the country. Place-names were removed from railway stations, shops, vans, advertisement hoardings, etc., and local maps from stationers’ shops. Arrangements were made to immobilise gas, electricity and water undertakings, to place all petrol pumps out of commission and to deny to a landing force coastal and inland bulk storage supplies of essential foods and commodities. Stocks at East and South coast ports were to be moved inland in an emergency or, if necessary, destroyed.
For the supervision of these tasks, and for the co-ordination of military and civil plans, the Chiefs of Staff set up a Home Defence Executive, under the chairmanship of the C.-in-C. Home Forces, with representatives of the Admiralty, Air Commands, Air Ministry and the Ministry of Home Security. The Executive held its first meeting on the 11th May.
The 1st Armoured Division Goes to France
As the threat of invasion was not regarded as immediate the War Cabinet, on the 11th May, at the request of the C.-in-C. British Expeditionary Force, authorised the despatch to France of the 1st Armoured Division which included all the medium and cruiser tanks in the country. These tanks were equipped with the 2-pdr. anti-tank gun; and their departure left only 168 light reconnaissance tanks, armed with machine-guns, as the armoured force for Home Defence.
The Loss of the French and Belgian Ports
The main German offensive against Belgium and France opened on the 14th May, the day after Dutch resistance ceased. Within a week, by the 20th May, a German armoured column had reached Abbeville on the Channel coast. On the 22nd, with a southern flank established along the Somme-Aisne river line, German armoured forces swung northwards on a wide front towards Boulogne and Calais while other German forces pressed westwards through Belgium and French Flanders.
On the 24th the Prime Minister5 asked for an effort to be made to close the Straits of Dover to enemy shipping by the use of long-range guns – the largest Dover guns at the time, two 9.2-inch, had a range of 17,000 yards and the Straits at their narrowest were 38,000 yards across. On the same day an area ten miles deep around the East and South coasts, from Kinnaird’s Head (Aberdeenshire) to Christchurch (Hampshire), was declared a prohibited area in which control of the movement of persons was to be in the hands of the military authorities.
On the 26th the French Premier, M. Reynaud, intimated that French resistance might soon be at an end. By the 27th the German forces had occupied Boulogne and Calais; and the British, French and Belgian divisions in the northern sector of the battlefront, north of the Somme, were being pressed from east and south into a narrowing bridgehead around Dunkirk. That night evacuation to the English coast was in full swing.
On the 28th the C.-in-C. Fighter Command told the War Cabinet that owing to the additional commitment to protect the Allied forces on the Continent the Fighter Force for Home Defence had been “reduced almost to cracking point”. The Prime Minister thought that the enemy might take advantage of the situation to send in a heavy attack against the United Kingdom. The Chiefs of Staff agreed; and on the following day, the 29th, they warned the War Cabinet “as a matter of urgency and as military advisers to the Government” that it was highly probable the German Command was now setting the stage for a full-scale attack on this country and that the attack might be imminent.
On the 12th June Mr. Churchill, after a meeting with the French Premier, told the War Cabinet that effective resistance by France as a great land power was coming to an end. “We must now concentrate everything”, he said, “on the defence of this island.” He viewed the new phase of the war with confidence. A declaration that we were firmly resolved to continue the war in all circumstances would prove the best invitation to the United States of America to lend us their support. “We shall continue the blockade” he added, “and win through, though at the cost of ruin and starvation throughout Europe.” On the 17th June the French Government accepted the German terms for an armistice.