The case for the expansion of Heathrow Airport has not yet been proven, says London Assembly members.

Sir Howard Davies, chairman of the Airports Commission, was grilled by the AMs on his controversial recommendation to build a third runway at Heathrow Airport, at a Q&A session on Tuesday (September 8).

The questions covered every hot issue surrounding the expansion debate, including the recommendation for night flights, noise and air pollution, congestion and the economy.

Val Shawcross, Labour AM for Lambeth & Southwark, proposed the motion that the case for expansion had not been proved, saying: “While accepting the need for expansion of airport capacity in the South East, this Assembly believes that the case for the expansion of Heathrow has not yet been proven.”

She added: “It is clear that the case for the expansion of Heathrow has not yet been proven and there remain serious questions about the environmental, noise and public transport impact.

"Whilst not insurmountable, Government would have to insist on far stronger measures to tackle air pollution and to manage the dramatic impact expansion would have on the transport network.

“Although important for economic growth, the Government cannot just nod Heathrow expansion through without proper scrutiny. There’s a long list of concerns which need to be addressed before I could see Heathrow’s expansion going ahead.”

The was motion was unanimously agreed by 13 votes for and none against, but a total of 11 Labour AMs abstained.

Speaking after the vote, GLA Conservative Andrew Boff said: "By fudging their position on Heathrow expansion, Labour have sacrificed their principles by putting the interests of their Mayoral candidates above Londoners.

"The truth is Tessa Jowell is for Heathrow expansion, Sadiq Khan is against, and that leaves our Labour colleagues on the London Assembly in a pickle.

"Today they chose to worry about political power rather than the interests of those they serve.

"We’ll carry on opposing a third runway at Heathrow and fighting for the interests of Londoners."

Mayor of London, and Uxbridge & South Ruislip MP, Boris Johnson said: "Conservative Assembly Members have today demonstrated that they are representing Londoners in opposing any extension of Heathrow, which would be an environmental disaster.

"This u-turn from London Labour, who campaigned against expansion at election time, shows why they cannot be trusted to run our city."

'Far from clear-cut'

In the Davies commission recommendation, a ban on night flights was suggested as a mitigating circumstance.

Richard Tracey, Conservative AM for Merton & Wandsworth, posed the question: “Your report calls for a third runway at Heathrow to be mitigated by a number of measures including the banning of night flights. Can you confirm that, if those mitigating factors were not introduced, then you would no longer support a third runway?”

Sir Howard Davies responded: "Our analysis to the results of the consultation and also what local people were saying to us suggested that the flight between 4.30am and 6.30am were dis-proportionality troublesome to communities.

"These were the flights people were most concerned about. We believed that we should look carefully at what should be done about it.

"After analysing the places that they came from, we believed they could leave later. It would affect some passengers, but largely transfer passengers.

"But overall we believe the impact would be manageable by the airport and airlines."

James Lee, of the Aviation Environment Federation (AEF), said: "Heathrow Airport itself is resisting quite strongly to the partial ban on night flights in the 4.30am-6.30am period so you'd expect the government to be quite clear as to whether or not it would go with that condition.

"Heathrow should be able to meet that ban quite easily, so the fact that they're resisting is a particular issue for those next to the airport."

John Stewart, chairman of HACAN, added: "It is clear from Howard Davies' remarks that the case for a third runway is far from clear-cut."