The boulder signals a point in time and a concrete idea of the launch

Curator Mike Stanley

Frankland has placed adverts in climbing magazines to encourage climbers to take on the challenge.

"It will be animated by climbers over the next two weeks - the artist doesn't see it as a sculpture but as a boulder," curator Mike Stanley told BBC News Online.

'Concrete idea'

The boulder is one of three arts projects which are intended to herald a major refurbishment programme at the Warwickshire house, culminating in a re-opening of its permanent collection in April 2003.

The sculpture is set in Capability Brown gardens

"The boulder signals a point in time and a concrete idea of the launch and a projection into the future," said Mike Stanley.

"The other projects are a radio station set up by Marcus Coates which will collect impersonated bird sounds from around the world, and broadcast them within the grounds of Compton Verney.

"And there will also be the work of Tim Brennan, a performance artist who will be leading walks around the house - the public can wander the empty galleries."

While the house is not scheduled to reopen as an art gallery for another two years, the parkland and empty galleries will be open for the public from two weeks on Saturday.

The permanent collection, which will be exhibited whole again in 2003, includes British portraiture from the 15th to 18th centuries, Neapolitan art from the late Renaissance, Chinese bronzes and British folk art.

Portland stone, mined in the south western county of Dorset, was used by Sir Christopher Wren to rebuild St Paul's Cathedral between 1675 and 1710.