Operation Sealion – Part 4

Blown Periphery, Going Postal

The Army and Defence in Depth

A number of senior members of the Imperial General Staff thought the likelihood of a German Invasion to be ludicrous. They believed the best strategy was to bolster the crumbling French Army. An additional Brigade of the First Armoured Division was duly sent to France where it lost all of its tanks, infantry carriers, artillery and logistics train. Air Chief Marshall Dowding refused to send any more fighters to France as he was husbanding his forces for defence against the air assault that would have to follow. This made him few friends within the Government and IGS and he was sacked as AOC Fighter Command after the Battle of Britain. The Fighter Command pilots had a valid reason to feel aggrieved that the Army blamed them for their own shortcomings leading up to Dunkirk. Over the nine days of Operation Dynamo, the RAF flew 171 reconnaissance, 651 bombing and 2,739 fighter sorties. Fighter Command claimed 262 enemy aircraft, losing 106 of their own, losses worse than they would experience in the upcoming Battle of Britain. There were recorded instances of RAF personnel, including shot down aircrew being refused entry to the boats out of Dunkirk; a shameful escapade in modern British military history.

The defence of Britain was encapsulated in the Julius Caesar Plan that was by now hopelessly static and built around a much larger standing army. General Ironside was the Chief of the Imperial General Staff and on 27th May 1940 was appointed Commander-in-Chief Home Forces. Ironside commanded a force which amounted – on paper – to Fifteen Territorial Infantry Divisions, a single armoured division, fifty-seven home-defence battalions, and the Local Defence Volunteers (later the Home Guard). However, all of these were deficient in training and organisation, as the operational units had already been sent to France. They were also lacking in equipment; the force as a whole had almost no modern artillery or anti-tank guns, and the armoured division had just a small number of light tanks. Intelligence was also hopelessly wide of the mark. Some estimates put the German strength at 44 Divisions with the entire RAF being outnumbered four-to-one.

The deficiencies with equipment led to an overall lack of mobility, which coupled with the limited training of the units meant that very few were capable of organised offensive counter-attacks against an invading force. As a result, the only way they could practically be used would be to commit them to static defence; Ironside planned to steadily pull units away from the coast and into a central mobile reserve, but this was not possible until they were trained and equipped for the role. He threw himself into the details of the strategy, laying out plans for the static defence of village strong-points by the Home Guard, patrols of “Ironsides” armoured cars to strengthen the divisions and light artillery mounted on trucks as improvised tank destroyers.

Blown Periphery, Going Postal
The GHQ Stop Lines

By early July there was a scanty mobile reserve in the form of an understrength 8th RTR. A network of pillboxes, anti-tank ditches and roadblocks were constructed and were known as the “Stop Lines.” The map above shows the main defensive positions with a fortress around the Bath/Chippenham area. Corsham would be the Government’s final redoubt in England if London fell. This major works programme would have taken five years in peacetime. It was completed in two months. What became known as the “Ironside Plan” consisted of the following defence in depth:

  • A defensive “crust” along the coast, able to fight off small raids, give immediate warning of attack, and delay any landings.
  • Home Guard roadblocks at crossroads, valleys, and other choke points, to stop German armoured columns penetrating inland.
  • Static fortified stop lines sealing the Midlands and London off from the coast, and dividing the coastal area into defensible sectors
  • A central corps-sized reserve to deal with a major breakthrough
  • Local mobile columns to deal with local attacks and parachute landings
Blown Periphery, Going Postal
Disguised pillbox added to a house

However, criticism of the “Ironside plan” was soon manifest. On 26 June (only a day after the plan’s approval) at a meeting of the Vice-Chiefs of Staff, Air Marshal Richard Peirse pointed out that many of the RAF’s main operational airfields would be overrun by an invader before reaching the principal GHQ Stop Line. Senior Army commanders complained of the plan: We have become pill-box mad.” There was widespread concern that troops were spending their time constructing defences rather than on the training which they desperately needed.

Another critic was Major-General Bernard Montgomery, never known for hiding his light under a bushel, who later wrote that he found himself “in complete disagreement with the general approach to the defence of Britain and refused to apply it.” When Churchill visited Montgomery’s 3rd (Regular) Division on 2 July, he described to the prime minister how his division, which was fully equipped except for transport, could be made into a mobile formation by the requisitioning of municipal buses, able to strike at the enemy beachheads rather than strung out along the coast as ordered.

Ironside’s position was also compromised by his relationship with “Boney” Fuller, who was a senior member of the British Union of Fascists. The Ironside Plan was very much of its day, the General making the best use of his limited and static resources. However as the summer of 1940 drew on more formations and transport became available and as importantly more guns and ammunition. Ironside was replaced by General Brooke on 19th July and a new strategy implemented. The coastal crust was to be more strongly defended with anti-tank islands or “hedgehogs,” making use where possible of the stop lines and a large, mobile reserve. Emergency Coastal Batteries were constructed to protect ports and likely landing places. They were fitted with whatever guns were available, which mainly came from naval vessels scrapped since the end of the First World War. These included 6 inch, 5.5 inch, 4.7 inch and 4 inch guns. These had little ammunition, sometimes as few as ten rounds apiece. At Dover, two 14 inch guns known as Winnie and Pooh were employed. There were also a few land based torpedo launching sites.

Blown Periphery, Going Postal

The map above shows the dispositions of the Southern Defensive Area’s formations around late summer 1940. It is a snapshot in time as the placement of the defensive units was extremely fluid. The most likely landing areas are strongly defended with Regular units, while the other coastal areas are covered by the Home Guard. The Isle of White and the Solent, Hastings, Folkestone and Dover are particularly well defended.

© Blown Periphery 2018