A race against time

Coastal erosion means the base of the Belle Tout lighthouse now stands just three metres (10ft) from the cliff edge at Beachy Head.

Plans to move the building 17 metres (55ft) inland have been put off until Tuesday.

Mark Roberts: It is an incredible feat of engineering

The 165-year-old structure will be raised 60cm above its foundations and moved backwards on rails. The operation will be completed during the Megalab '99 television programme on 17 March.

Regular rock falls mean owners Mark and Louise Roberts have little choice but to move house - literally.

Costly delay

The entire operation will cost them �180,000. They could have applied for a grant but Mr Roberts says the delay might have proved catastrophic.

Everything beneath the skirting boards has been removed

"It got to be a major event in November last year when we lost about 20ft of our front garden.

"We had to mobilise the engineers to come down and do the work," he told the BBC.

All the building's foundations have been removed - everything under the skirting boards has now been replaced with a network of concrete and steel.

Sliding track

The plan is to lift the building in stages of just a few centimetres using 30 small jacks connected to a hydraulic engine and controlled by a computer. Once secured at the right height, the building will be run back on a steel plate and oiled neoprene sliding track.

The lighthouse will run back on greased rails

There is a small concern that the operation itself could trigger a major collapse of the cliff, sending the lighthouse tumbling into the sea.

"The worry is when we actually first engage the jacks to move it," says Mr Roberts. "Obviously there is an opposite and equal reaction - if we are moving the lighthouse one way, there is energy being put down on to the cliff pushing it the other way."

Temporary foundations

If all goes well, the Belle Tout lighthouse will be put down on the site of an old croquet lawn.

The family could not wait for a grant application to go through

The engineers will build the new foundations so that another move can me made more easily in the future.

The East Sussex landmark was built in 1834. Lighthouse duties were transferred to a new building constructed on the rocks below Beachy Head in 1902. Belle Tout became a private residence from the 1920s.