The head of British Airways' parent company on Tuesday warned that Heathrow will be overtaken by Dubai as the world's biggest international airport "within two to three years".
Speaking to the House of Commons Transport Committee, IAG chief executive Willie Walsh said that the Dubai airport had grown massively over the last decade.
He told MPs that in 2001 Dubai was the 99th biggest international airport in the world and by 2011 it was fourth.
Walsh claimed UK politicians had been afraid to take tough decisions on airport expansion which had been "kicked into the long grass" and would stay there for "a considerable time", UK media reported.
He told the committee that he believed there would still be only two runways operating at Heathrow even as late as 2050.
"New runway capacity is required, but I don't believe that capacity will be provided," Walsh reportedly said.
The Government has set up an aviation commission headed by former Financial Services Authority chief Sir Howard Davies which is due to finally report on aviation capacity in the summer of 2015.
But Walsh said he was "not optimistic" that the Davies Commission would lead to any expansion any time soon.
In October, Dubai Airports CEO Paul Griffiths called Boris Johnson’s proposal for an £80bn aviation hub in London's Thames Estuary “unfundable”.
Griffiths urged the UK Government to back a third runway at Heathrow because “Boris island” cannot be built in time to ease the UK's lack of airport capacity.
He contrasted Heathrow — which is near full capacity at 68 million passengers annually — with Dubai, which by 2018 will have doubled capacity to 90 million passengers.