The British Chamber of Commerce (BCC), a business lobby, said that capacity restraints at Heathrow, the world's busiest international airport, had led to it falling behind competitors such as Schiphol in Amsterdam and Frankfurt in Germany.

If a third runway is built, it will add up to £30 billion to the economy, the chamber said, including productivity gains and wider economic benefits such as new jobs.

'By reducing delays and increasing the frequency of flights, a third runway would save business passengers time and increase their productivity, the report said.

'Passengers would also benefit from flights to new destinations, removing the need to wait for transfers at airports outside Britain,' it added.

The government has approved the building of a third runway but environmental campaigners and other pressure groups are opposed to it and construction has yet to get the go ahead.

'This comprehensive study clearly outlines the economic benefits of expanding Heathrow - an important part of the debate which too few people fully understand,' said David Frost, the director general of the BCC. 'Without additional capacity at our major hub airport, we will continue to fall behind our continental competitors. The age old phrase 'time is money' is apt as we look for solutions going forward,' he added.

Environmental groups, climate change campaigners and people living near Heathrow argue that another runway and terminal will cause widespread environmental damage and pollution, while increasing congestion with knock-on negative economic impacts.

A new runway would take about 10 years to build, expand traffic to 600,000 flights a year from 480,000 and create new flightpaths across London. -- Reuters