The London Assembly rejected Heathrow expansion proposals at a meeting today and suggested more use be made of spare capacity at other airports.

Members passed a motion in reaction to the interim report published by Sir Howard Davies’ Airports Commission and the options proposed for expanding Heathrow and Gatwick.

Conservatives said the Lib Dem motion opened the door for more flights at Heathrow due to the support it showed for increased capacity in the south-east.

Tony Arbour, Conservative London Assembly Member for Richmond and Hounslow, proposed an amendment which said there should be a categorical opposition to any additional flights at Heathrow.

He said the Lib Dem motion, which recognised the need for more airport capacity in the south-east, “opens the door for dual use of runways at Heathrow which will increase noise for millions of Londoners.

He said: “I, and my Conservative colleagues, are unequivocally opposed to any increase in flights at Heathrow and we, unlike the Lib Dems, will not consider any concession to those who would increase the pollution that the airport brings to residents.”

Caroline Pidgeon AM, who proposed the motion, said she was disappointed to see Heathrow expansion back on the table.

She said: “Airport capacity in London is currently under-used, in fact some London airports have more than half of their runway slots free.

“Rather than inflict further misery on the residents of west London, the Davies Commission should rule out expansion of Heathrow and focus on better use of capacity at other south-east airports.”

Liberal Democrats branded Tories expansion-supporters after all Conservative members voted against the motion.

Robin Meltzer, the Liberal Democrat parliamentary spokesman for Richmond Park, said: “It’s no longer the case that the Tories are split on Heathrow.

“Now, almost everyone they have in elected office is in favour of mass expansion or, at best, isn’t bothered. The few who are on our side of the argument are simply sidelined by their leadership.”

MP Zac Goldsmith, who has long made clear his opposition to Heathrow expansion and organised a mass protest rally against additional runways last year, hit back at Lib Dem claims, and said their failure to back Coun Arbour’s amendment meant they were standing in the way of true opposition to Heathrow expansion.

He said: “The fact remains that the Lib Dems could have removed Heathrow expansion from the terms of reference of the Airport Commission without any effort at all.

“That would have killed it off forever, but they chose not to because they see the threat as a campaign opportunity.

“Putting it mildly - for those seriously committed to stopping Heathrow expansion, the Lib Dems have been a real pain in the backside.”