Sound familiar? Haig's performance as Hacker in the recent stage show of the series prompted several people to compare the character to the bumbling-yet-popular Boris Johnson, Mayor of London and – if the Westminster grapevine is to be believed – wannabe Prime Minister.
"I didn't base Hacker on anyone but others have mentioned Boris – probably because he's got that combination of being a very clever politician but sometimes he seems like anything but," says Haig, a seasoned theatre actor perhaps best recognised for playing bonking groom Bernard in Four Weddings And A Funeral.
The actor, dressed in a trendy lumberjack-style jacket, is sitting in London's National Liberal Club, a fitting location to discuss the political satire, being a stroll away from Downing Street.
Yes, Prime Minister was a sitcom created by Antony Jay and Jonathan Lynn which ran from 1986 to 1988 as a sequel to Yes Minister, which ran for four years from 1980. At the heart of the series was the tempestuous, symbiotic and farcical relationship between elected ministers and civil servants, as embodied by Harker and his Permanent Secretary, Sir Humphrey Appleby (played by Paul Eddington and Nigel Hawthorne respectively).
In 2010 the writers decided to adapt the story for the stage, updating it with a plot which took in the coalition government and economic crisis. Haig took on the role of Hacker and Henry Goodman played slippery secretary Sir Humphrey.
The play was such a success that it has now been adapted for TV again, using the same lead actors, meaning Haig has to transfer his performance from the stage to the studio and try to live up to the original television version.
He claims not to be fazed by the latter, saying: "Think of the number of times characters such as Jeeves and Wooster have been played by different actors, and the comic relationship between Jeeves and Wooster is similar to that between Jim Hacker and Sir Humphrey.
"Hacker and Humphrey are like many double acts. To say they like each other would be grossly inaccurate but they are interdependent. And their status shifts all the time; one or the other gets the upper hand, both believe they are right a lot of the time.
"I think the battle for power is what is so appealing, that's what's funny to watch."
Yes, Prime Minister's return to our screens is timely. Not only is it an era of much soul-searching regarding the integrity of our politicians, but the new series comes just a few months after the final episode of The Thick Of It.
Armando Ianucci's political satire was inspired by Yes, Prime Minister, but rather than focusing on the clout of the civil servants, it satirised the ministers who cower under the influence of Westminster's all-powerful spin doctors.
Haig appeared in this too, playing weasel-like Chief Whip Steve Fleming.
"It strikes me they're similar and dissimilar," he says. "They are both acute political satires but with great characters and great relationships, and they are both funny.
"The main dissimilarity to me is stylistic: In The Thick Of It you feel as if you're going in through a little side door and in this room where people happen to be behaving and reacting, whereas Yes, Prime Minister is a much more theatrical event – it's a beautifully modulated, intelligent sequence of events, and it has structure.
"Part of The Thick Of It's beauty is it doesn't adhere to the conventional structure."
Though he doesn't class himself as an "I-must-get-to-the-conference-on-time" sort of person, Haig says he's a "political animal" who's supported Labour his whole life.
He names Labour leader Ed Miliband as today's most likeable politician. "I'm warming to him," says Haig. "It's great when someone does it against the odds."
Haig himself is consolidating his screen credentials by winning the lead role in The Wright Way, Ben Elton's forthcoming sitcom about a newly divorced health and safety inspector.
"I think it's extremely funny, like all of Ben's stuff," says Haig of the new show, which begins filming in Manchester this month.
"In the best possible way he takes risks and it's going to be very exciting."
It's always hard to predict future success at the time of making, and Four Weddings And A Funeral is a case in point. The 1994 film, written by Richard Curtis, broke box office records and launched Hugh Grant to global stardom.
Haig admits: "We only realised how big it was when we were invited to the distribution party for Czech Republic or Ukraine."
Yes, Prime Minister, perhaps also surprisingly, has global appeal and has been remade in other countries, including Israel, Holland and India.
And though the new version has been conceived as a single series, Haig and his colleagues aren't ruling out doing more.
He says: "It would be ridiculous if we said we weren't hoping."
After a successful stint on the stage, the rebooted version of Yes, Prime Minister is returning to TV screens – with David Haig playing the lead. He tells Lisa Williams about taking on
the popular role.