When Boris Yeltsin retired from politics in 1999 it left a hole in the schedule of Alex Pfeiffer, the New York born comedian who had played him on Saturday Night Live. Looking for a new character, Pfeiffer had a chance meeting with two British comedy writers, Barney and Brienna Cheatem, who were in New York on holiday.

Pfeiffer was fascinated by the then moribund nature of right wing UK politics, with William Hague’s Conservative party polling in minus numbers, and Blairism still ascendent. Between them, the Cheatems and Pfeiffer crafted a right-wing comic character for British politics, retaining the “Boris” name for their initial improv sessions, and deciding not to abandon it when they couldn’t come up with anything better.

With Pfieffer unknown in the UK (Saturday Night Live didn’t air there), the Cheatems saw the opportunity to, in a sense, pretend the character was real, rather than presenting him as overtly fictional. “We liked Alan Partridge,” admits Brienna, acknowledging the obvious inspiration without a pause. “Boris”, in Pfeiffer's conception, would be an absurd character, verbose but prone to misusing words, from a privileged background, but with an intimidating thuggish demeanour reminiscent of a drunken bully at a bus stop.

“We initially wanted him to be a fictional character whom you enjoyed watching, despite them repeatedly doing ridiculous or vile things – like Jeremy Clarkson, or Dot from Line of Duty,” explains Barney, “But, as with Johnny Speight and Alf Garnett we found we’d created a satirical fictional device that people not only took seriously, but which they actually supported.”

“Boris” won the Mayoralty on a “Ha Ha, No, He’s Only Joking” ticket. The ludicrous nature of many of the plans he came up with for London, didn’t seem to dent his popularity, either. “The dangleway,” laughs Brienna, “Boris Island? And the Garden Bridge. I mean, seriously? We were absolutely hammered on Ouzo when we came up with those. Yet the first is there, used by no one except Arsenal’s advertising men, bleeding money, and the third will probably go ahead too, despite being in the exact spot where anyone can see London really absolutely definitely doesn’t need a new bridge at all.”

The Bridge was the ultimate expression of an idea of Pfieffer’s – that the childish “Boris” had a passion for alliteration, resulting in over-budget, largely useless “Boris Buses”, ridiculously heavy “Boris Bikes” and so on. “We thought that them being sponsored by Barclays would be a problem,” acknowledges Barney, “Bankers aren’t exactly anyone’s favourite species right now, but there was so little problem that when that sponsorship lapsed, we went with one from Santander, despite it not beginning with B.

“I think Alex was a bit upset by that, actually.”

Some critics argued that the "Boris" character predicted the rise of other politicians across the Atlantic. Image: Getty.

Despite these obvious failures, “Boris” grew in popularity. The duo responded to this unexpected turn in their writing: “We tried hard to darken ‘Boris’,” says Brienna, “When Channel 4 broadcast that phone call where he agreed to hand over the personal details of a journalist to someone who wanted to physically threaten them... We thought that might dent his popularity. But no.”

“When he stayed on holiday while London literally burned, there was surprisingly little comeback,” Barney interjects, rubbing his chin. “I thought that would cause us more problems to be honest, it’s not a very plausible plot development in what’s meant to be a mature western democracy.”

The claim in Boris’ biography of Winston Churchill, that he was the only Prime Minister to lead troops in battle, was intended by Pfieffer and the writers as a turning point. “It’s obviously ludicrous,” notes Brienna, “And exactly the sort of thing that annoys the middle english types that “Boris” was meant to appeal to. Even ignoring that the Duke of Wellington was Prime Minister twice, it’s very clear that, with Attlee, MacMillan and Eden in there, Churchill struggles into the top five most militarily distinguished British Prime Ministers in his own War Government.”

Yet again, there was little comment on this absolutely howling error – one that would have been used to destroy a book on the topic by literally anyone else alive. Even before anyone noticed that the same volume claimed the Germans captured Stalingrad.

In response, the writers gave Pfieffer – up to that point on a relatively tight lead when it came to public improvisation – more leeway to be absurd off his own bat, hoping this would have some impact. “When he shouted ‘In the name of god and mammon, go!’ about the Occupy movement – a statement that makes no sense at all on any level, no matter how hard you try and excuse it – we really thought the wheels might come off. But no.

“Then that foul mouthed breakdown on the BBC during the 2012 election? Again, it was reported, but nobody really cared,” comments Barney, still clearly amazed. “It’s almost as if no one in the Britain was remotely interested in holding him to account on any level. We really couldn’t work it out.”

With another London mayoral election imminent, Pfieffer, Barney and Brienna are now done with “Boris” – tired of a joke that, they acknowledge, was played out long ago and was never really as funny in practice as it seemed that first night in New York. Pfieffer has some voiceovers to do for Dreamworks, and is missing his native NYC.

Meanwhile Barney and Brienna are writing material for a retired geography teacher who has inexplicably found himself near the top of another political party. “The Left are as hopeless now as the Right were when we came up with Boris – it was time for a change of target. The jokes are easier on the other side right now, and maybe we’re getting lazy as writers.”

Yet “Boris”, with his £250,000 a year column in the Telegraph, has made all three of them rich – so why not keep the character going? Why not stand for a third term?

“Pfieffer’s performance fees, which have been getting exponentially larger, are paid out of an Arts Council grant that, as of a year after the last general election, no longer exists,” admits Barney, “Without that subsidy, the maths don’t work and this obviously implausible creation just isn’t financially viable.

“In austerity Britain, we all need to tighten our belts.”