In September 1914, with the Allies advancing after their victory at the Marne, Joffre suggested that the British land a force at Dunkirk to threaten the German right flank; at Kitchener's suggestion Churchill took over the mixed force of marines and yeomanry. Churchill was soon making frequent trips to Dunkirk, where he had set up a RNAS squadron and some units equipped with Rolls Royces which had been turned into "ad hoc" armoured cars. He arranged for 70 London buses to be used for extra mobility.