Theresa: "Oh, please, yes."

And so it was done.

On Thursday, at a summit in Sandhurst, British Prime Minister Theresa May promised France tens of millions of pounds to beef up security in Calais, to fast-track the processing of asylum seekers bound for Britain from France, and for military support for France's anti-Islamic militant operations in Mali.

In return, she got a loan of a big tapestry, maybe, in four years' time, and a stern lecture from President Emmanuel Macron on what Brexit doesn't mean (special access to European financial markets for the City of London), however much Britain would wish it to.

"Merde," May probably said to herself, picturing the next day's newspapers. This entente cordial was tasting pretty watery.

Enter the foreign secretary Boris Johnson, who has a reliable talent for setting the news agenda, sometimes even on purpose.

"Britain should consider building bridge to France, says Johnson" splashed the next day's Times.

"Boris calls for bridge across the Channel", the Daily Telegraph blared.

Mysteriously, neither had an actual quote from Johnson to this effect. The closest he came to proposing it in public was an ambiguous tweet.

But in the Telegraph he was "understood to have told aides" there should be a bridge across the Channel.

And in the Times he was "understood to think" that just having one tunnel (yes, pedants, there are three) is ridiculous and they should explore the idea of a bridge across the Channel.

The Times added that Macron was "said to have backed the idea", telling Johnson: "I agree - let's do it".

Now that sounds a surprisingly blunt quote for the suave and canny Macron. It sounds more like, say, some other person. Someone not afraid to stretch the truth when the occasion demands.

The next day a spokesman for Macron told the BBC that Macron had responded instead with: "The issue of access is an important one," which sounds an entirely more likely and diplomatic way of saying "whatever, Boris".

Of course, I'm imagining most of these details. But given the whole story is based on making stuff up to fill newspapers, what the hell.

It was a masterstroke.

Everyone loves a big bridge.

Boris has a less-than-great history on bridges. As mayor of London he authorised the waste of tens of millions on an eventually-scrapped plan for a ??200 million ($364 milion) ???garden bridge' across the Thames, an idea whose loveliness is only beaten by its pointlessness.

Then there's the ??60 million ($104 million) cable car link from somewhere in East London to the O2 Arena which is busy carrying cabins of empty air across the Thames, and so-called ???Boris Island', a ??47 billion ($81 million) brainwave to build an artificial island in the Thames Estuary to house a new airport which was only ever taken seriously by one person, and possibly not even him.

According to engineers frantically summoned to 24/7 TV news on Friday, a bridge across the Channel might be best done by building at least two artificial islands in the Channel, so cars can briefly go through a tunnel and ships can go over the top.

A bridge and multiple new islands. Right in Boris' wheelhouse.

Majestic, cheeky and slightly absurd.

But, hang on. Is it?

In 1981 engineering group LinkToEurope submitted a detailed proposal for a ??3 billion ($5.2 billion) motorway on a suspension bridge across the Channel. The consortium even said it had backing for the entire project from private financiers, who would recoup their investment from tolls.

They conceded that building it would make navigation tricky in one of the world's most congested sea passages, but they showed the supporting pylons could be made strong enough to withstand a collision.

A few years later, when the UK government was seriously considering Channel spanning options, a consortium called EuroRoute proposed a three-section solution: an 11-kilometre road bridge followed by a 20-kilometre tunnel then another bridge, which would sit over the top of a rail Channel Tunnel. The project's brochure, unearthed by website CBRD, is impressive.

Others asked on Friday: wouldn't the bridge have to shut down whenever it was a bit windy, which in the Channel is quite often? But the EuroRoute consortium insisted it would be "an all-weather, 24 hour a day facility".

No, the boffins say it can be done. Maybe they're right.

But that was never really the point.

Theresa: "Boris, I don't think that summit with France went very well."

Boris: "Oh, build a bridge and get over it... Hang on... that gives me an idea."