But the plans, which also include a new terminal, have been attacked by campaigners concerned at the loss of green field land.

A report by the airport also looks at the need for a rail link between the Midland main line and the East coast main line, and road links between the M1 and A1M.

The airport, which handles about six million passengers a year, could see this figure rise to 85 million.

We would have concerns as to the impact of the new runways and the increase in passenger numbers

Andrew Critchell, CPRE

The proposals are put forward in the airport's submission to the government's study into the future of air transport.

The report presents two options with the first being to extend the existing runway and building a second one capable of handling between 62 and 85 million passengers a year.

The second option would see the single runway replaced by two new parallel runways running in a north east to south west direction.

Presenting options

The new terminal building would link to a rail line across Hertfordshire between Luton and Stevenage.

Airport spokesman Ian Briggs said the report is simply presenting proposals to consider.

Andrew Critchell, campaigns officer on aviation for the Council for the Protection of Rural England, said he was concerned at the plans.

"We would have concerns as to the impact of the new runways and the increase in passenger numbers," he said.

"We are also against any building on green belt land."