The Department for Transport contributes annually towards the Department for Environment, Food and Rural Affairs (DEFRA) Procurement of Food and Catering Services Report which can be found at:
http://www.defra.gov.uk/foodfarm/policy/publicsectorfood/awareness.htm
The report gives details of the proportion of domestically produced meat, fruit and vegetable purchased. The figures for 2008-09 will be published by DEFRA at the end of 2009.