The controversial war-zone comedy returns for a second tour of duty as we catch up with bomb disposal unit Bluestone 42 in Helmand Province, where the humour is as dark and blue as ever. Tony Gardner (Fresh Meat) is back at the top of the food chain as Lt Col Philip Smith, coolly exerting his leadership over hot-blooded troops who bicker and battle as a distraction from the ever-present threat of attack. While Captain Nick Medhurst (Oliver Chris) weighs up his handgun against that of new arrival Cpl Gordon House (Matthew Lewis), Padre Mary Greenstock (Kelly Adams) announces a special award - to the 'filthiest bastard on the base'.

Oliver Chris: Nick & Mary's relationship takes a turn

"The episode is about being stuck in a horrible place over Christmas and how this unit get by."

Ah yes, that staple of Christmas television: the sitcom about a bomb disposal unit in Afghanistan. Actually, the first series of Bluestone 42 overcame a shaky, cliché-riddled beginning to mature into a pretty decent workplace comedy; a second series is due in the New Year.

No preview copies were available, but this one-off introduces one Corporal Gordon House (played by Matthew Lewis, familiar from his role as Neville Longbottom in the Harry Potter films), joining the team for his first tour of duty. Having excelled in training, House fancies himself even in the face of scepticism from his captain, Nick Medhurst (Oliver Chris). Might the new man's confidence prove misplaced? Well, what do you think? This may be a Christmas special with a relatively unorthodox theme, but don't go expecting too many surprises.

Borgen fans will be delighted to see Birgitte Hjort Sørensen (ambitious young newshound Katrine) guesting in cheekily lusty form - and speaking impeccable English - as a Danish aid worker called Astrid in this bomb-disposal squad sitcom.

She's got the hots for officer Nick (Oliver Chris), who's headline news for the way he handles his bombs.

And then to make himself even hotter, he goes and rescues her from the clutches of the Taliban. What a guy.

As the Afghanistan-based squaddie comedy continues to bed in, it's proving increasingly adept at handling the awkward balance of earthy humour and tense, life-or-death situations. Today, tetchy Captain Nick (Oliver Chris) thinks he's found a solution to the unending monotony of dull Army food when he hears of a supposedly tasty, though critically endangered, Afghan gecko - which just happens to populate the same area where his bomb disposal team is working. Can he clear IEDs while thinking of catching dinner?

Humour can be at its funniest when found in the darkest or toughest or most unlikely situations - and a British bomb disposal unit in Afghanistan ought to provide fertile ground. But so far this comedy-drama lacks subtlety and seems too puerile. In tonight's episode, team leader Nick (Oliver Chris, above) airs his complaints about the canteen food but then learns of a new - and endangered - food source that catches his attention, Millsy (Gary Carr) leads a retraining course and Simon (Stephen Wright) is ribbed about his age.

Radio Times review

Is now, or ever, the right time for a sitcom set among soldiers serving in Afghanistan? Bluestone 42 tested the question with its tales of a British army bomb-disposal unit.

Bluestone 42 is written by Richard Hurst and James Cary, who have both worked on Miranda and are experienced comedy technicians. They kept scenes to a minimum length, filled any gaps with gags, and efficiently established their characters and the central plotline of smooth captain Nick (Oliver Chris) chasing cute female padre Mary (Kelly Adams), who finds him attractive despite herself but constantly rebuffs him.

It was a bit too efficient. This was a fairly conservative workplace sitcom, hung on a talking point that was likely to get commissioning editors and journalists interested. There's no cause to doubt Hurst and Cary's research, or their interest in the subject matter. What is in question is whether the comedy and the subject matter meshed together in the right way.

The soldiers were comedy types: a fussy man, a tomboy, an exceptionally vulgar Scot, an omniscient boss (Tony Gardner) who pops up at inconvenient times. They schemed and joked with each other as the captain and the padre set a will-they-won't-they arc going. With Bluestone 42 unwilling to offer comment on the war itself, the driver for episode one's plot might as well have been a lost lever-arch file or someone scratching the MD's car.

In fact it was an American colonel (Mike McShane) being fatally shot in the head, the flip treatment of which might well have troubled you if you view Western soldiers in Afghanistan as making a grim but glorious sacrifice. But if you see them as oppressive occupiers, Bluestone 42 had that covered too. The Yank's death was softened in advance by his annoying habit of crowing endlessly about his tour of duty in Fallujah.

Fallujah. Fallujah. The word became a punchline. It's just one of those funny place names, isn't it? Like Penge, or Kidderminster. At least it might be for viewers who are a bit hazy on what happened to the locals there in 2004. Anyway, Nick the raffish captain sorted out all the palaver about the team being fired on by launching an RPG into the Afghans' hut, killing them all and letting us get back to the comedy.

Of course a sitcom in a warzone isn't off-limits. But Bluestone 42 shows that it's... a minefield.

Even before it's broadcast, this comedy has caused a furore, dealing as it does with a squad of bomb disposal experts clearing IEDs in Afghanistan. Can such a sensitive subject get laughs?

Yes it can. Richard Hurst and James Cary (who have both worked on Miranda) evidently did their research. The banter and camaraderie are as profane as you'd expect on the frontline, and some of the humour is exceptionally dark. However, that research seems to be holding them back; they're so careful presenting a balanced view of professional soldiery that the characters are underplayed.

There is promise in the lusty captain Nick Medhurst (Green Wing's Oliver Chris) and his pursuit of the attractive new padre (Hustle's Kelly Adams), but larger-than-life roles are in short supply. Michael McShane's CIA liaison officer Carter is one, but his appearance is all too brief.

"Too soon?" one character asks in ­Bluestone 42 after he makes a tasteless quip about the death of a CIA officer. That's the question you might be asking after watching BBC3's new sitcom about a bomb disposal team in Helmand Province. After all, it's usually polite to wait until a war is actually over before you start making jokes about it.

The Korean War had been done and dusted for more than 20 years before M*A*S*H waded in. The same goes for Dad's Army, while Blackadder Goes Forth waited a good 80 years for the dust from the First World War to settle.

And after the number of documentaries the BBC has made about Afghanistan - in particular Our War, also on BBC3 - the show's writers will have been acutely aware of the potential offence they could cause by making comedy out of conflict. It seems their main concern was getting all the military details right, rather than whether they should be making it at all.

But, putting all thoughts of whether Bluestone 42 is wildly inappropriate or not to one side, thank goodness that it's actually very funny, with an excellent line in banter.

Oliver Chris is perfectly cast as Captain Nick Medhurst - the officer who fancies himself a little too much as the dashing war hero, and expects the new female padre (Hustle's Kelly Adams) to feel the same.

The big ensemble cast also includes Tony Gardner (Lead Balloon and Fresh Meat) as the Lt Colonel, Katie Lyons as the blokeish Corporal Bird and a bomb-seeking robot called Arthur.

Meet the cast of Bluestone 42

We speak to Oliver Chris, Stephen Wight, Gary Carr, Kelly Adams and the other stars of BBC3's controversial new Afghanistan war comedy.