British Transport Secretary Grant Shapps | Dan Kitwood/Getty Images Transport secretary: UK could still scrap Heathrow airport expansion ‘There are questions about whether the whole plan stacks up,’ says Grant Shapps.

British Transport Secretary Grant Shapps on Wednesday said his office will have a “really close look” at whether plans to expand London Heathrow Airport are financially viable.

Speaking to Sky News, Shapps said, “There are questions about whether the whole plan stacks up.”

The plan to add another runway at Heathrow will cost £14 billion, much of it privately funded. “They’re going to need to make sure they bring in enough income to justify the billions of pounds spent on it, that’s something that we'll be taking a really, really close look at, I certainly will as the new transport secretary,” Shapps said.

The U.K. parliament voted in favor of expanding Heathrow airport in June last year. Prime Minister Boris Johnson — who represents a constituency near the airport — had previously strongly opposed the project. Johnson, then foreign secretary, was away in Afghanistan on the day of the vote.

Shapps has been a consistent supporter of the extra runway.

A coalition of environmental groups, local city councils and London Mayor Sadiq Khan are appealing to the courts to get an injunction against the project.

Asked whether his views on the project have changed since becoming the U.K.'s leader, Johnson said in July he is "following with lively interest the court cases."