Usually peregrine falcons like to nest on a cliff face

The birds raised two fledglings in 2002 and another last year in one of the towers of the derelict power station in south west London.

Work is due to start on developing the site into a complex of shops, restaurants and leisure facilities.

A 164 foot high steel tower has been built to encourage the birds to stay.

�500m scheme

The structure is designed to mimic a cliff face, the usual nesting place for peregrine falcons, and includes a covered ledge with gravel spread across it.

The tower was constructed with the help of environmental consultants Nicholas Pearson Associates.

Dr Mike Wells, from the company, said its success would not be known until the nesting season began in late winter.

"We cannot be certain that it will work", he said.

"The developers felt that the cultural and ornithological value of these birds was so great that we had to do everything we could to keep them in the area."

The �500m redevelopment scheme for the Grade II listed power station includes hotels, a theatre, cinema, flats and a dedicated rail link from Victoria station.

It is due to be completed in 2008.