Motorway may cost 2000 an inch

A five-mile motorway extension in Glasgow is expected to become Britain's most expensive road after its costs hit 657 million - or 2000 an inch.

Ministers admit the M74 link is expected to cost 131 million a mile, after delays and inflation increased the original estimate by half, compared with 79 million a mile for Britain's next-biggest road scheme, widening the M25 around London.

Work is expected to begin in May on extending the motorway from south-east Glasgow to the Kingston Bridge, creating a short-cut for through traffic and taking 20,000 vehicles a day off the M8.