By Matt Chorley, Mailonline Political Editor

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Boris Johnson today launched an astonishing attack on David Cameron, his foot-dragging on airport expansion is putting Britain on course for 'economic catastrophe'.

The London Mayor accused the government of paying 'lamentable attention' to the issue of increasing airport capacity.

Just days before the Tory party conference, the astonishing attack on his party leader will do little to end speculation of a leadership challenge.

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Boris Johnson today launched an astonishing attack on the government's aviation policy, just days before the Tory party conference in Birmingham

Boris Johnson today launched an astonishing attack on the government's aviation policy, just days before the Tory party conference in Birmingham

The two men had a 'clear the air' dinner at Chequers on Sunday designed to resolve tensions which have frequently spilled out into the public domain.

But today Mr Johnson used a speech to business leaders to make one of his most outspoken attacks on the government to date.

He said: 'The Government programme to address the looming aviation capacity crunch in the UK is far too slow and I am hugely concerned that their intended timetable sets a course for economic catastrophe.

'This continued inertia is being fully exploited by our European rivals who already possess mega hub airports that they intend to use to erode our advantage.

'I will continue to work with the Government and the Davies Commission, but the urgency of the situation and the lamentable attention that the Government has paid to this pressing issue has forced me to accelerate the work that I will do to develop a credible solution.'

Mr Johnson opposes a third runway at Heathrow airport and wants a four-runway airport, possibly in the Thames Estuary and possibly at Stansted airport in Essex.

Mr Cameron promised to block a third runway before the 2010 election but pressure from business and the Treasury has raised the prospect of a u-turn.

With just days before the Tory party conference begins in Birmingham, Boris Johnson's extraordinary attack on David Cameron's government will further damage relations with Number 10

The government has now asked Sir Howard Davies, a former head of the Financial Services Authority, to lead an independent commission into airport capacity.

But the final report is not due until summer 2015 - after the next general election.

Mr Johnson said the scale of the location required for a new hub airport with at least four runways meant sites, including Heathrow, Gatwick, Birmingham and Luton, had to be ruled out.

A new 180 million passenger a year hub airport would cost 75 billion to 80 billion.

While Mr Johnson has flatly denied wanting to replace Mr Cameron, his increasingly frequent outbursts have caused a headache for Number 10.

When Andrew Mitchell, the Chief Whip, had an angry confrontation with police guarding Downing Street, Mr Johnson said it would have been 'common sense' for officers to arrest him.

The Mayor has also supported calls from the Tory right for an 'in-out' referendum on Britain's membership of the EU, something Mr Cameron has so far resisted.

VIDEO: Boris calls the government's aviation policy an 'utter disgrace'

The comments below have not been moderated.

Conservative Party in-fighting ... awful. I've had enough of it - I'm switching to that Mr Milliband at the next election. - Steve, London..........Please DO NOT switch to Milliband, and do not forget 13 years of the Labour government. I never will. Give UKIP a chance.

I am with Boris, we need another Airport central England is where it should be . I said so 20 years ago. Why do the people in Power wait till everything is at a Critical stage ?

Oh dear, the Torys are certainly divided, and we haven't even got on to the EU debate yet.

Oh by the way did he forget to mention the £30bn road and train infrastructure costs, that aren't part of the build, and aren't to be funded by private equity, this £30bn will be funded by the tax payer through road tolls and increased fuel taxation, so the poor majority in the rest of the UK will be priced off the road to allow the rich in London to get to their desk 15mins earlier

Oh god financial meltdown if the few cant fly!!!

I think it would be accurate to claim that his government was on course for economic catastrophe - not just because of Cameron's airport plans, but plainly due to his Chancellor's basic incompetence right across the board, where finance is concerned.

Boho just ruined his rep. Bad BOJO!!

BoJo for PM!

Yeah, go on then. Put Boris in charge. The Tories have been electing the wrong person to lead them (with the possible exception of Heath) since MacMillan. One buffoon following another; should ensure at least 25 years in opposition.

Tories - tax cuts for millionaires only. It would be precisely the same with Boris in charge. Face it, they are a busted flush.

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