A leading business lobby group appealed yesterday to the Conservative party to reverse its opposition to the building of a third runway at Heathrow airport, warning the policy would cost the economy billions of pounds in lost productivity.

A study published yesterday by the British Chambers of Commerce said the direct economic benefit of adding capacity at Heathrow would be in the region of £300m-£500m a year.

Not building the runway would cost the economy between £8.6bn and £12.8bn in lost productivity over 60 years and would jeopardise wider economic benefits totalling £20bn.

David Frost, director general of the BCC, said: 'We must invest now to safeguard our economic future or we risk wasting £30bn fumbling around for an alternative.'

Financial Times, Daily Telegraph