Structural engineers are assessing the damage in Boscastle

The total cost of rebuilding the village could be as much as �500m, according to a former president of the Institution of Structural Engineers.

Brian Clancy says the "questionable" foundations of many properties in the village means it will be cheaper to knock them down than to rebuild them.

Structural engineers are currently assessing the damage in Boscastle.

You may get a house that looks okay but you might have to make a judgement on whether to demolish it or not in three or four months when the water is dried out Brian Clancy Former president of the Institution of Structural Engineers

Mr Clancy told BBC News Online: "A judgement has to be made on a lot of these properties.

"Is a building so damaged that it's more economic to demolish it or to rebuild it?"

He said that because Boscastle was an old village the foundations of many properties would be "questionable".

"In a lot of old buildings, not only will they be questionably founded but their super-structure would also be questionable because of alterations," he added.

"Because they've aged, they deteriorate with time and the force of the water was colossal."

Dry rot

A lot of the houses would have been "very fragile" before the floods hit and were previously "standing up just because they were standing up."

"If you were balancing on one leg you could almost continue standing indefinitely but if someone gave you a nudge you would fall over," he said.

He said the extent of the damage would not be immediately clear because timber in flooded properties took "a long time" to dry out which could lead to "all sorts of problems" including dry rot.

"So you may get a house that looks okay but you might have to make a judgement on whether to demolish it or not in three or four months when the water is dried out," he said.

The flooding in Boscastle was a "financial disaster as well as a human catastrophe".

"We could be looking at as much as �400 or 500m-worth of damage," he added.

Damaged foundations

Malcolm Tarling, of the Association of British Insurers agreed that, as well as the obvious damage seen in TV pictures of Boscastle, the unseen damage caused to structures and foundations could lead to many more homes being destroyed or rebuilt.

"That's something that is going to be investigated in the coming days," he told News Online.

There will be further damage to structures and foundations Association of British Insurers

"We've seen the horrific pictures of people's homes and contents already destroyed but many more could be affected.

"There will be further damage to structures and foundations."

He said that, although it was too early to say how many properties would have to be demolished altogether, he understood about 80 properties had been affected by the flooding "to a lesser or greater degree".

"But this is why people take insurance out," he added.

"There will undoubtedly be millions of pounds of damage. This is a freak accident."

Liz Kennett, of Norwich Union, said the damage in Boscastle was more obvious with buildings that had been completely swept away.

"But there will be different degrees of damage depending on where buildings are on the main hill in Boscastle," she said.