The discovery was made when the bird's mating call was heard by a farmer in the Pennine Dales earlier this summer.

Corncrakes are one of two species listed as globally threatened which breed in the UK.

Government officials devised a management plan that protected the corncrake chicks but meant the farmer could continue working his land.

I'm impressed and heartened at the speed and effectiveness with which everyone involved in this extraordinary project acted

Elliot Morely, conservation minister

Conservation minister Elliot Morley said: "I'm impressed and heartened at the speed and effectiveness with which everyone involved in this extraordinary project acted.

"The result is a significant conservation achievement, and very exciting news for the English countryside."

The last count of corncrakes, in 1998, recorded 589 singing males, which were until now confined to the north of Scotland and Ireland.

The birds are so rarely seen that they can only be identified by the distinctive rattling sound made by the males, so the number of females is unknown.

Action in the 1990s halted the decline but numbers fell dramatically in the early part of the 20th Century, largely due to the introduction of mechanised mowing in farming.

Cutting pattern

Martin O'Hanlon, senior adviser for the conservation area, said: "Once we knew the bird was there we took every precaution we could to ensure that if any eggs were laid, the chicks would have the best possible chance of survival."

A bird-friendly mowing pattern, which would allow any chicks to escape to the edge of the field, was agreed with the farmer.

Experience gained in Scotland showed that cutting from the middle of a field outwards gave the chicks a chance of survival by moving to the edges of the field.

When the farmer, whose identity has not been disclosed, cut his meadows he reported seeing two chicks running clear.

The RSPB is to undertake a major census of corncrake numbers in 2003, which should indicate if this year's success has been part of a wider trend.