LONDON (AP) — Britain may be leaving the European Union, but Foreign Secretary Boris Johnson wants to build bridges with the Continent. Literally.

Johnson has suggested that the U.K. and France should build a bridge across the English Channel to bolster links between the two nations after Brexit.

At a U.K.-France summit on Thursday, Johnson said the idea of a bridge was worth considering. He said it's ridiculous that countries 20 miles (32 kilometers) apart are linked only by a single railway tunnel.

"Our economic success depends on good infrastructure and good connections," Johnson tweeted. "Should the Channel Tunnel be just a first step?"

Johnson neglected to mention that there are also sea and air links between Britain and France.

Ian Firth, past president of the Institution of Structural Engineers, said Friday that a bridge was "entirely feasible." But shipping firms warned it could disrupt one of the world's busiest shipping lanes.

At Thursday's summit the two countries pledged to set up a panel of "eminent and qualified persons" to examine "significant projects."

Prime Minister Theresa May's office said there were no specific plans for a cross-Channel bridge.

Johnson has a penchant for large infrastructure projects. As mayor of London he backed a "garden bridge" over the River Thames, a project that was scrapped by his successor, Sadiq Khan, as poor value for money.

Johnson also championed building a new airport in the Thames estuary, a project dubbed "Boris Island" by the press. The idea was rejected by an inquiry looking into airport expansion.