Councils opposing a third runway at Heathrow are set to unveil plans showing how the airport could instead be used as a rail hub for up to 40 trains an hour.

The 2M Group will reveal the plans on Thursday, the day after a Commons vote on the expansion of the airport.

Their blueprint, Getting to Heathrow, will show how the number of trains passing through the airport could match the number of planes it currently accommodates.

A Heathrow rail hub would link 150 stations within a 25-mile radius of the airport to mainline services, including a high-speed line from London to Scotland.

Campaigners say it could take a million cars off the road every year.

"The Government's plans for a third runway include a £4.5bn high speed Heathrow hub,” said Wandsworth Council leader Edward Lister on behalf of 2M.

“This is nothing more than a high speed hoax as just about all the costs will be swallowed up by a 15-mile tunnel to St Pancras.

"Our scheme is practical and offers much better value for money.”

The 2M group, formed of 21 councils representing 4m residents, developed the plans as part of its support for alternatives to Heathrow expansion.