A group of Conservative MPs and a think tank have suggested two more runways be built at Heathrow, to no surprise to anti-expansion campaigners.

The Free Enterprise Group and think-tank Policy Exchange made their suggestions in reports released this week.

At the same time the London Assembly has suggested noise from Heathrow and its impacts on people living nearby be reduced.

Richmond Heathrow Campaign, which is against a third runway, said there was little of surprise in the reports.

Chairman Peter Willan said: “It’s what we and other campaigners anticipated as probable and statement is just confirmation of that.

“We think the environmental costs of a third runway are going to be huge. A fourth just won’t be viable.”

However he added: “It’s quite good that they’re now coming clean.”

All proposals will be considered by the Davies Commission, headed by Sir Howard Davies, tasked with identifying and recommending to Government the options for maintaining the country’s status as an international aviation hub.

A Heathrow spokeswoman said: “We don’t endorse either proposal but we do believe the Davies Commission should consider any option for a single airport capable of handling the UK’s future hub capacity needs.

“Like all the options, these have their strengths and their weaknesses, which is why the Davies Commission needs to undertake a thorough analysis of them all. We will respond fully to the commission’s consultations when they are published.”

The London Assembly health and environment committee (HEC) said last week that an independent body should administer the airport mitigation and compensation schemes, which could help to rebuild the trust lost by local communities.

It also said noise measurement should be consistent, the detrimental impact on people should be reduced and suggested airports work together to organise flight times to reduce noise.

HEC chairman Murad Qureshi said: “Tackling the impacts of aviation is a big issue, both globally and for the people who live close to airports and bear the brunt of the detrimental effects. They could be in danger of serious health consequences.

“As politicians and experts gear up to discuss various options for airport expansion, there are understandably concerns that more runways and airports will bring increased noise and emissions which will seriously affect people’s quality of life.”

The Government’s draft Aviation Policy Framework was published in July by the Department of Transport.

The consultation period, which closed last week, will allow views to be given on a range of environmental concerns.

The HEC committee’s responses will feed into a final plan, which will then be consulted on twice over the next year, before new guidelines for airports are adopted from 2014.

Environment spokesman for Richmond’s Green Party James Page said: “I think when you ask people, not connected with aviation, they would be happy to see growth constrained. Even businessmen can find a way to get to most places on the globe – direct flights aren’t vital.

“Basically we have to get used to the idea that we cannot continue to grow all industries forever – and growing airports is not top of the list. And I’m pleased to see that Howard Davies has CO2 emissions on his agenda too.”