We don’t know when it’s going to happen, we don’t know how it’s going to happen, but one thing's for sure - Karen Gillan is set for a “heartbreaking exit” during the next series of Doctor Who.

With the Doctor’s flame-haired companion heading off into the unknown with Arthur Darvill’s Rory in tow, the Tardis is going to start to feel a little empty, but happily there’ll be a non-specific “new friend” joining everyone’s favourite Gallifreyan before long.

Who could it be? You might well ask. You see, Britain's awash with hot young acting talent at the moment, so there are lots and lots of possibilities to speculate about. Which is, coincidentally, what we’ve done here.

So here are the people we think would make decent companions on the show. Have a look, vote in our poll, and if your favourite hot young actor or actress isn’t there, post a comment and put us right…

Hannah Murray

Brilliant as Cassie in Skins, since then she’s gone quiet - perhaps mainly because she was studying for a degree. Indeed, this was the reason she ruled herself out of the running in 2009 when there were rumours she would get the role that ultimately went to Karen Gillan. She’s got a classic companion’s mix of girlishness and steel – and she’s acted opposite Matt Smith before, in bizarro 2010 supernatural cloning film Womb.

Freddie Fox

Fox turned in a memorable performance last year as ambitious rent boy Ratallack in The Shadow Line, and this year made a big impression in Dickens drama The Mystery of Edwin Drood. As a member of the Fox acting dynasty, he’s cousin to Lewis star Laurence, who’s married to Billie Piper – she could certainly provide some tips on how to play the Doctor’s companion! 

Chipo Chung

Chung has already made an appearance in Doctor Who – with minor roles as Chantho in Utopia and the fortune teller in Turn Left – but that didn’t do Freema Agyeman’s chances any harm. Chung had a recurring role in Camelot and recently popped up as a reporter in Sherlock episode The Hounds of Baskerville. She’s not a star yet - but she deserves to be.

Aneurin Barnard

The We’ll Take Manhattan star is the kind of sparky discovery that Doctor Who tries to make with its companions: add to it extensive stage acting and the kind of film roles that make it odds-on he’ll be a big star soon, he’s at exactly the right point in his career to join the Doctor.

Charlotte Ritchie

As eager-to-please Oregon in Channel 4's university comedy Fresh Meat, Charlotte did kooky and gangly very well. She also showed herself to be a very good actress as she dealt with her increasingly creepy and inappropriate relationship with a lecturer. She's wide-eyed and offbeat - a bit like the Doctor, but also like many of his successful companions.

Adam Gillen

Ever the quirky character, Adam has been popping up all over the shop on TV for the past few years, most notably as the unlucky-in-love Liam in ITV comedy Benidorm, as Howard’s sidekick, Brian, in Fresh Meat and, more recently, in the BBC drama Prisoners’ Wives. If you’re in any doubt that Adam has what it takes, listen to this: he has red hair (like Karen Gillan), he has the surname Gillen (almost like Karen Gillan)… and he’s been in The Sarah Jane Adventures, Doctor Who’s little brother – surely he’s a shoo-in for the role.

Kimberley Nixon

Another Fresh Meat alumnus, Kimberley exudes that (albeit very pretty and smart) girl-next-door vibe that has characterised previous companions such as Sophie Aldred's Ace. She'd make a good foil for the occasionally ditzy Doctor, practical, questioning, a little bit feisty and not afraid to get her hands dirty when events call for it.

Jack O'Connell

Best known for Skins and This Is England, he can play the young and cheeky type, for ever getting into scrapes and needing a Time Lord to help him out. He's acted with one before: he co-starred with David Tennant in United.

Louise Brealey

With Steven Moffat and Mark Gatiss at the helm, there’s a significant fandom crossover between Sherlock and Doctor Who. The actress who made timid lab technician Molly so endearing could easily make the jump (sorry) to the Tardis. Having a feminist on board might also appease viewers who think character is more important than the length of the character’s skirt.

Thomas Turgoose

Another one from This Is England, Turgoose is one of those young performers who already looks like being a character actor with a long career ahead of him. A career that the Tardis could boost.

Lisa Greenwood

Best known on TV for The Hour - and she’s currently filming a second series - Greenwood is another one who is plainly companion material because she’s playing exactly that alongside Colin Baker’s Sixth Doctor in a trio of Big Finish Doctor Who audios this year.

Daniel Kaluuya

One of Radio Times’s rising stars for 2012, if you didn’t catch Kaluuya on the silver screen as Rowan Atkinson’s sidekick in Johnny English Reborn, you may well have seen him on your TV screen instead. He was wise-cracking Mac in BBC3’s The Fades and starred in Fifteen Million Merits (one of three episodes in Charlie Brooker’s Channel 4 mini-series, Black Mirror), under the watchful eye of many times Who director Euros Lyn.