At least 90 per cent of eggs served to schoolchildren and hospital patients come from battery chickens, campaigners claim.

Campaigners have called on the practice to stop and for public bodies, using taxpayers' money, to buy eggs from free-range chickens.

Of all the eggs sold in supermarkets, 47 per cent are free-range, according to sales figures, suggesting that public procurement officers are not reflecting national trends.

Earlier this year the Office for National Statistics threw out battery eggs from the shopping basket used to calculate the Consumers Prices Index, in favour of free-range eggs. Most caged birds have less than the size of an A4 sheet of paper, on average, as their living space.

On Tuesday Chris Mullin, the Labour is expected, in a speech, to call for legislation that will prohibit the purchase of so-called caged, or battery, eggs in the public sector and require purchase of free range eggs.

He said: said: “It is important that government leads by example to support animal welfare. Prohibiting public sector organisations from buying cage eggs would make a huge difference to the welfare of millions of hens. Government has a responsibility to use public money wisely to support ethical food choices.”

Some NHS trusts have started to buy free-range, but a campaign group called Good Food for Our Money, has called on all to adopt the policy, even though the eggs cost more. The campaign estimates that 40 out of the 468 local authorities have declared themselves caged-free.

European Union legislation will ban all caged hens by 2012, but many farming groups believe this will lead to imports of battery eggs from outside of the EU.

Daily Telegraph 3/11/09