A report released by the House of Commons Environmental Audit Committee said firm plans need to be in place dealing with climate-change emissions, air quality and noise.
The committee’s chairman Labour MP Huw Irranca-Davies said it would be irresponsible of the government not to deal with the environmental impact of a new runway at Heathrow, adding it could be open to legal action if it doesn’t.
He said: "If the government decides to accept the commission’s recommendation for a third runway in principle, we will seek assurances from the secretary of state for transport that environmental conditions will be met before it is given final approval.”
The committee also said legal air pollution limits would be required as well as a ban on night flights while the airport would also have to prove it would be quieter with three runways than two.
It also urged the airport to pick up the cost of surface transport improvements.
Irranca-Davies said: "The communities living near to the roads around Heathrow already put up with noise and extra traffic.
"It would be quite unacceptable to subject them to a potentially significant deterioration in air quality as well.
"Planes are becoming more fuel efficient, but this alone will not keep aviation emissions in line with the government’s climate change targets given the growth in passenger numbers.
"Even without expansion, aviation is on track to exceed its climate change target.
“We heard evidence that those targets might be met in theory, but at present there is a policy vacuum and evidence-based scepticism as to whether they can be met in practice."
