London Mayor Boris Johnson will risk the wrath of Prime Minister David Cameron today by highlighting "unnecessary" delays in formulating aviation policy.
Mr Johnson is expected to repeat calls for his Thames Estuary airport scheme, dubbed "Boris island".
In a speech to business leaders, the mayor is likely to be critical of the timescale of the recently announced, Whitehall-commissioned independent report on aviation being headed by former Financial Services Authority chief Sir Howard Davies.
Some have accused the Government of kicking the aviation debate "into the long grass" by announcing that Sir Howard's full report will not be completed until summer 2015 - after the next general election.
It is thought Mr Johnson will today say that he considers this timescale "nonsensical" and that the commission could present its findings in 12 to 15 months.
He is also expected to tell his audience at City Hall in London that the delays in aviation policy are not only unnecessary but "artificial".
It is almost two years since Mr Johnson published a document calling for a new airport for London and he has consistently maintained his position since.
In his foreword to the January 2011 publication, Mr Johnson said Heathrow was "not the answer" and that Britain had failed to act on aviation and had been "paralysed by the difficulties rather than recognising the opportunities".
Former transport secretary Justine Greening also opposed a third runway at Heathrow and Mr Johnson was highly critical of Mr Cameron's decision to replace her in last month's Government reshuffle.
Last weekend Mr Johnson and his family visited the Camerons at Chequers, with the two men enjoying a pub lunch amid discussions described as "wide-ranging".
Both men have played down suggestions that Mr Johnson, buoyed by the success of the Olympics, is a rival to Mr Cameron as Tory leader.