As the RAF presence in France was reduced, its aviation fuel requirements fell and by 5 June most RAF aircraft had returned to England, yet deliveries continued. British armoured units were also less demanding of fuel as the number of vehicles dwindled, until the main users were the transport echelons of the front-line units and the lines-of-communication troops, which could be supplied by the fuel delivered up to the end of May. Karslake wrote that the small number of armoured vehicles removed from France was a mystery and that a train with the last tanks of the 2nd Armoured Brigade and some of those of the 3rd Armoured Brigade, departed from Le Mans for St Malo and disappeared. It was rumoured that the train had been sidelined by the French and the engine removed for another train but no effort was made by the road parties outside Brest to find their vehicles. No party accompanied the vehicles and no aircraft reconnaissance was sought, even though the Germans were a long way from Brittany.