Foreign Secretary Boris Johnson has floated the idea of building a bridge across the English Channel to link the UK with France.

Mr Johnson, who as Mayor of London infamously sought to promote the idea of an offshore island airport in North Kent, has apparently turned his attention to another potentially controversial idea.

He is understood to have broached the idea with the French president Emmanuel Macron during his state visit.

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In a tweet, he said: “I’m especially pleased we are establishing a panel of experts to look at major projects together.

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

But some experts have questioned the viability of a bridge crossing what is the busiest shipping channel in the world.

Mr Johnson apparently believes it is ridiculous there is currently only one link between the two countries in the form of the Channel Tunnel.

A report in the Daily Telegraph said the Foreign Secretary believed there should be more than one rail link connecting what he said were Europe's two biggest economies.

Johnson is said to think a bridge could also be possible, telling aides that such feats of engineering have been achieved in Japan.

The idea has won the support of Dover MP Charlie Elphicke, who said: "Boris is right. We absolutely must invest in infrastructure to keep trade flowing between Britain and France.

"Let's start by dualling the A2 to Dover, and building the Lower Thames Crossing and lorry parks on the M20.

"Surely it's not a bridge too far for the Government to invest in Kent."

Mr Johnson is said to have told aides:"Technology is moving on all the time and there are much longer bridges elsewhere, including one that is 34 miles long in Japan."

The Guinness World Records says the Lake Pontchartrain Causeway in Louisiana, USA is the longest bridge over continuous water at 23.79 miles - which is just about the width of the English Channel at its narrowest point.