It’s a truism of the impersonator’s art that those who can do other voices have none of their own. On Parkinson, Peter Sellers couldn’t even come down the staircase as himself. When at the end of the show Mike Yarwood said, “And this is me!” a nation switched off. The idea behind The Mimic, starring the remarkable Terry Mynott, is that it accepts the truism as truth. This is a comedy about a man who can pose convincingly as Ronnie Corbett stuck in a postbox but has no life to call his own.

Will Franken is an odd-bod. The American - Missouri-born, now a San Francisco resident - is a character comic and impressionist, but not in the way we understand a Rory Bremner or an Alistair McGowan. He “does” famous people, for sure, but these are fleeting impersonations in a wonderfully free-flowing affair that weaves swiftly between stories and builds an hour of increasingly absurdist humour.

There must be something about doing a medical degree. A steady stream of medics - including Jonathan Miller, Graham Chapman, Graeme Garden and Paul Sinha - have hung up their stethoscopes to plough a furrow in comedy (Phil Hammond, meanwhile, manages to combine the two careers). It was definitely medicine's loss and comedy's gain when Harry Hill made his career detour and, as he gleefully tells us in Sausage Time, five years at medical school provided him with the wherewithal to deliver an educated (and very funny) fart gag.

There are oodles of comedy DVDs released for the Christmas market - here's a selection of the best.

Dara Ó Bríain
Craic Dealer

Susan Calman's star has risen of late - the Glaswegian lawyer turned stand-up has been an Edinburgh Fringe favourite for some while now, but in the past two years she has become an established Radio 4 presence through the likes of The News Quiz, and has been seen acting on television on shows such as Sharon Horgan's comedy drama Dead Boss.

Alan Davies used to be a regular on the stand-up circuit, before acting and other television work, including ad campaigns and being a panellist on the long-running quiz QI, took him away from live comedy. But now, after a break of more than a decade, he's back on the road and the rest has clearly served him well.

Among the many things Jenny Eclair does these days - writing novels, panto, appearing on television in various guises - she has found time to go back on the road with Eclairious. TV hasn't curbed her deliciously potty mouth, thank goodness, and even though she says by way of introduction “Please lower your expectations”, she proves to be on fine form, as ever.

“When I was a teenager even I had a period when apparently I was quite morose,” Jack Dee tells the Edinburgh crowd, his hangdog features projecting various extremes of existential agony. “But, hey, I got through it." This may be Dee’s first standup tour for six years, but it’s very much business as usual in terms of perpetuating his role as comedy’s Mr Grumpy, eternally exasperated, irritable, acerbic. And, truth be told, these days a tiny bit predictable.

For the past few years Russell Kane has mined much of his comedy from his fraught relationship with his father, now dead. It's a neat twist then to postulate his latest show, Posturing Delivery, on his relationship with "Ivan", Kane's entirely imaginary son.

If the first rule of being a novelist is to write about what you know, then the first rule of comedy is to be yourself. And in that respect Shappi Khorsandi starts with an advantage, as being herself means she's warm and likeable and the audience are instantly on her side. And when it comes to her material, she started in stand-up with another advantage, in that her parents had to escape persecution in Iran (her father is a satirist who upset the ayatollahs), and for a while the family were given protection officers when they moved to London.