A Thames estuary airport would cost twice the current £50 billion estimate for the project, according to former transport secretary Lord Adonis.
London’s mayor Boris Johnson has promoted the idea for an estuary airport and plans for a separate project in the area have been produced by leading architects Foster & Partners.
Adonis said that Fosters’ £50 billion estimate for the new airport was likely to have “many billions added” to the cost if it went ahead. Adonis was the minister who approved a third runway at Heathrow in 2009 when the last Labour government was in power.
“I would be surprised if we were not talking about £100 billion-plus because it would involve a second Thames barrier and a new high-speed link to London,” said Adonis at a session during World Travel Market in London.
Adonis added that he was “not dismissing it out of hand” and that the estuary airport should be given “a fair wind” as part of the independent commission being led by Sir Howard Davies into solving the lack of airport capacity in the south-east.
The commission will not report fully until after the next general election in the summer of 2015. Although there will be an interim report by the end of 2013 looking at short-term fixes to the capacity squeeze.
Adonis said the government had been forced not to take a decision before the next election because of the Liberal Democrats being “virulently against” a third runway at Heathrow.
He added that he thought that if the Conservatives had won a majority in the 2010 general election, the government would have “found a way to ratify” the previous Labour government’s decision to build the third runway. Adonis was part of the government that approved the extra runway in 2009.
“Never has one public policy issue been so analysed,” said Adonis. “Six or 12 months would have been ample, instead of three years that has been given to Davies.”
He also urged neither the Labour or Conservative parties to explicitly rule out expansion at Heathrow in their next general election manifestos.
“To rule out expansion at Heathrow would be barmy and could undercut the role of the Davies Commission,” he added.
He said that both parties would come under pressure in the run-up to the next election to declare their opposition to a third Heathrow runway.