Britain's Foreign Secretary Boris Johnson, right, and Britain's Home Secretary Amber Rudd attend a ceremony at the Royal Military Academy Sandhurst, west of London on Jan. 18, 2018. (Ludovic Marin/AFP/Getty Images)

LONDON — As Britain prepares for its departure from the European Union, there has been ample discussion about the building of bridges as Britain finds its new place in the world.

And maybe that means building an actual bridge.

Britain’s flamboyant foreign secretary, Boris Johnson, sparked a debate about the possibility of a 22-mile bridge spanning the English Channel. Currently, the two countries are linked by an undersea rail tunnel known as the Channel Tunnel.

Johnson reportedly raised the idea of a Channel bridge with the French President Emmanuel Macron at an Anglo-French summit on Thursday.

Johnson tweeted a picture of himself and the French president, both giving a thumbs up, with the caption:
“En marche! Great meetings with French counterparts today.”

He also said that a panel of experts had been set up to review “major projects.” He then asked: “Should the Channel Tunnel be just a first step?”

But France’s finance minister didn't foresee anyone bridging the Channel just yet.

“All ideas merit consideration, even the most far-fetched ones,” Bruno Le Maire told Europe 1 radio, according the Reuters news agency.

“We have major European infrastructure projects that are complicated to finance,” he said. “Let’s finish things that already under way before thinking of new ones.”

It wouldn’t be the longest sea bridge ever built — that honor goes to a 26-mile bridge in China that opened in 2011. But the U.K. Chamber of Shipping suggested that building a massive bridge in one of the world’s busiest shipping lanes could pose difficulties.

A spokesman for British Prime Minister Theresa May said all ideas for big-picture projects are welcome, but questioned whether Johnson's concept for the cross-channel bridge was anything more than just a dream. “I haven’t seen any plans on that,” the spokesman said.

Others pointed out that, technically, it’s possible. And building such a crossing has been considered before. In 1981, when Margaret Thatcher’s administration was mulling designs for the Channel Tunnel, plans for a three-lane suspension bridge were submitted to transport officials.

“It’s certainly possible,” said Ian Firth, the former president of the Institution of Structural Engineers.

He said that the biggest challenge would be the risk of ships colliding with the bridge, but added that it could be dealt with using technology including artificial intelligence, GPS and “significant vessel impact protection.” He said that such an endeavor would take eight or nine years.

Nigel Farage, the former leader of the nationalist U.K. Independence party, slammed the idea as dangerous and a waste of money.

But many also questioned the motivations for floating the idea. Perhaps it was meant as a distraction from Thursday’s summit where Macron rejected special post-Brexit access for Britain’s financial services unless Britain played by the existing E.U. rules. Others ventured that Johnson, an ambitious politician, was seeking to grab headlines and possibly trying to undermine his boss.

“Boris Johnson's Channel bridge isn't infrastructure, it's an ego trip,” ran a headline in the Guardian.

Johnson has a history of proposing large-scale infrastructure projects that have not taken off. He campaigned heavily for an airport in the Thames estuary, dubbed “Boris Island” by the British media, which was discarded in favor of building a third runway at Heathrow airport. He also backed a garden bridge across the River Thames, a floral crossing that some said could be London’s answer to New York’s High Line. It was scrapped by Sadiq Khan, Johnson’s successor at City Hall.