British Foreign Secretary Boris Johnson attends an official dinner at the Victoria and Albert Museum in London.

The British government has played down U.K. Foreign Secretary Boris Johnson's proposition of building a bridge from Britain to France.

Johnson said a 22-mile crossing to connect the U.K. and France should be built across the English Channel, according to several British media reports Friday.

A spokesperson for Prime Minister Theresa May was reported later to have said that there were no such plans. Speaking to CNBC, a spokesman said that plans for Johnson's bridge between the two countries had not been seen by the government, adding that the foreign secretary was referring to a panel overseeing major Anglo-French infrastructure projects.

Johnson, who has served as foreign secretary since May took power, apparently made the suggestion for a bridge across the Channel at the Sandhurst military academy in southern England on Thursday, during French President Emmanuel Macron's first official visit to the U.K.

The Daily Telegraph and Sky News reported that, when Johnson made the suggestion, Macron said: "I agree, let's do it."

According to the Telegraph, Johnson said that it was "ridiculous" the two countries were "linked by a single railway," the Eurostar.

The minister has previously supported the idea of building a road tunnel beneath the Channel, and was a big advocate for London's Garden Bridge — a failed £200 million ($278 million) project to build a bridge across the River Thames covered in trees and shrubbery — during his time as the capital's mayor.

Britain's departure from the European Union was high on the agenda during Macron's visit. U.K. Prime Minister Theresa May will offer France £44.5 million ($62 million) to improve border security in Calais and other ports along the Channel, while the leaders also signed a treaty to speed up the processing of migrants in the coastal French town applying for asylum.