Defra has admitted whipping up the latest headlines on free-range egg fraud.

A spokesman said he tipped off newspapers about a new lead in its investigation into a Midlands-based company accused of re-labelling battery eggs as free-range. The aim was to provoke a public response to CCTV pictures of a man wanted in connection with the investigation, which has been running since October.

"We've had a few calls, but it's too early to say if any yielded leads," he said.

Free-range egg producers have backed Defra's move, in spite of the resulting headlines claiming up to a billion eggs were mislabelled.

"It doesn't do any good for consumer confidence, because people will think it's a fresh case. But I'd prefer the case to be sorted out rather than kept quiet," said British Free Range Egg Producers' Association chairman John Widdowson.

Meanwhile, Sainsbury's has said it will move all its eggs to free-range as soon as British supplies are available.