mobile reserve in the form of the 7th Royal Tank Regiment. Ironside's plan for the defence of the United Kingdom, included the construction of "stoplines". In his words "... strong points prepared for all-round defence at aerodromes ... at the main centres of communication, and distributed in depth over a wide area covering London and the centres of production and supply" with the intent of preventing "the enemy from running riot and tearing the guts out of the country as has happened in France and Belgium." In Scotland, Scottish Command ordered a series of stoplines to be completed. The main line was to run from Dysart, Fife to Loch Tummel, with an additional line built from Cowie, Aberdeenshire inland. These lines were to include wire obstacles, anti-tank barriers, and pillboxes. The 9th (Highland) was to construct the Cowie Line, and aid in the preparation of Scottish Command's other defensive efforts. The division assisted in the construction of beach obstacles, rigged bridges for destruction and established roadblocks. The 274th Field Company, Royal Engineers was vital in the opening stages of the Cowie Line construction. Other changes included the 5th Queen's Own Cameron Highlanders being transferred from Tain to Halkirk. The battalion was assigned to defend RAF Castletown, which provided air cover for Scapa Flow. Disbandment Following the evacuation at Dunkirk, 140,000 British soldiers remained in France. Most were lines-of-communication troops (such as those organised as the Beauman Division), but they included the 51st (Highland) Infantry Division. The latter, on 6 May 1940, had been assigned to the French sector of the front near Saarland, between Colmen and Launstroff, and positioned on the frontline between the border and the Maginot Line. As a result of the German advance during their invasion of France, the division had been cut off from the rest of the BEF. Under French command, the division was withdrawn towards the Somme after initial engagements with German forces on the border. By the time the division had arrived at Bresle, the BEF was already being evacuated via Dunkirk. At this point, the British government was determined to reinforce the French, and prepared to dispatch a new BEF as soon as forces became available. By 9 June, the 51st Division had started to withdraw towards Le Havre, after defending its position at Bresle. The intent was to evacuate the division from there. With this in mind, the 154th Brigade was