Defra countered claims last week by Conservatives that much of the £2bn public-sector food budget went on produce from abroad (Grower, 5 December).
But farming and environment minister Jane Kennedy said the public sector was using increasing amounts of British food.
"Small and local producers are the lifeblood of our food industry," she said. "That's why we've made such an effort to increase the amount of local, seasonal food served by public bodies."
She said latest figures showed the NHS supply chain now sourced 70 per cent of its food from domestic sources, compared with 58.5 per cent a year ago.
The Ministry of Defence, meanwhile, had increased the amount of British produce it used from 43 per cent last year to 59 per cent in 2008. And figures from the prison service revealed an increase in use of British produce from 37 per cent to 49 per cent this year.
"If you eat an egg in a hospital, government canteen or army barracks in Britain, that egg will be British, and the milk in your tea will almost certainly be British. This is the result of the Government's drive to buy more local produce and support local businesses."
She added: "Buying local food and eating with the seasons where it is possible reduces the impact on the environment and supports our businesses."
She said the Government would "look further" at how to increase the amount of British food it bought and improve chances for small firms tendering for contracts.
"This aims to increase tendering opportunities for small and local food producers to help them win contracts to supply government departments and other public bodies."
Kennedy added that the recent figures formed part of a monitoring initiative of public-sector food procurement.
Shadow environment secretary Peter Ainsworth last week called for a "presumption" in favour of UK farm-assurance standards or their equivalent in UK food contracts.