A cross-section of Lord Foster's plans for a new Thames Estuary airport

by political editor Paul Francis

Liberal Democrats have voted overwhelmingly against plans by London Mayor Boris Johnson for a Thames Estuary airport.

At the same time, party delegates have reaffirmed they do not support plans for a third runway at Heathrow or expansion at other airports such as Stansted and Gatwick.

Delegates made clear their opposition to both ideas in a vote at their party conference in Brighton.

Dr Julian Huppert, Liberal Democrat MP for Cambridge and co-chair of the
parliamentary party committee on transport, told the conference Boris Island was "not a proper suggestion."

"It is, simply put, a bad idea. The location is wrong, the cost too high, the environmental damage too great, and that's just the start of the problems," he said.

Dr Huppert claimed passenger numbers could be increased by using capacity at existing airports in the UK, including Gatwick, Stansted, Birmingham and Manchester.

"We don't need to build new capacity, we need to use it better."

He added: "Our long-term vision is a new hub if we can find somewhere that's better than we already have, but only if we close other runways to make up for it, so there's no net increase in runways or total capacity."

It was time for the party to set out an aviation policy which "balances the need for growth with the clear environmental threat that we face".

He said: "Aviation is the fastest-growing contributor to our emissions, we simply must not build airport capacity which would force us to miss those carbon reduction targets, it's as simple as that."

Deputy Prime Minister Nick Clegg said ahead of conference he was "not persuaded by a Thames Estuary airport" but would wait for the findings
of the independent commission set up by the government.