From McCombs et al "World War II facts"

Michelin

French tire manufacturer who published road guides that were used by the British Expiditionary Forces to find their way to Dunkirk because the B.E.F. could not get adequate tactical maps from the War Department. One officer, Major Cyril Barclay, bought 80 maps in one of the small French villages and successfully led his unit to Dunkirk, but the War Office refused to reimburse him because " regulations offer no provision for an officer to buy maps on active service".

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