Book excerpt: It is said that 'an army marches on its stomach,' but histories of the First World War usually concentrate on its political and military aspects. The gargantuan task of keeping the British Expeditionary Force fed and watered is often overlooked, yet without adequate provision the soldiers would never have been able to fight. Tommy couldn't get enough tea, rum or fags, yet his commanders sent him bully beef and dog biscuits. But it was amazing how 2 million men did not usually go short of nourishment, although parcels from home, canteens and estaminets had a lot to do with that. Incredibly, Tommy could be in a civilised town supping, beer, wine, egg and chips, and a few hours later making do with bully beef in a water-filled trench. Alan Weeks examines how the army got its food and drink and what it was like.