Chris Ryan's Strike Back, Sky1

Chris Ryan and Andy McNab are the Pepsi and Coca Cola of gung-ho, modern SAS war fiction, a lucrative genre that these one-man brands have carved up so effectively between them that it would take a gate-crasher of Nick Clegg-like proportions to threaten their duopoly.

Both men retain their pseudonymous existence, more for the self-publicising drama of it than for security reasons - although Ryan rather ludicrously asserts that his life would be at risk if his real identity was revealed. Literary critics aren’t that savage, surely.

Admittedly I have never read any of Ryan’s books, although I did, out of curiosity at its cultural impact, consume Bravo Two Zero, McNab’s much-disputed factual account of an ill-fated SAS reconnaissance patrol during the first Gulf War, of which Ryan was also a part. I assume his writing shares the same visceral qualities – not to mention an authentic-feeling barrack-room racism that dubs Arabs as “ragheads”. If so, then Sky1’s new six-part adaptation, Chris Ryan’s Strike Back, has been considerably toned down for family audiences - although the effect of bullets on flesh is as graphic as any shoot-‘em-up computer game.

Made by Andy Harries’ Left Bank Pictures, purveyors of Wallander, Prime Suspect and much else, and starring Richard Armitage from Spooks, Andrew Lincoln and Jodhi May, the first two episodes were written by Jed Mercurio (Cardiac Arrest, Bodies), the former doctor turned great white hope of British TV drama. That’s a lot of talent to invest in what is essentially a not very bright pot-boiler, in which Armitage plays John Porter (perhaps Ryan nodding obliquely to Look Back in Anger, but then perhaps not), an SAS man who, during an operation on the eve of the 2003 invasion of Iraq to rescue a kidnapped British businessman, takes pity on a teenage boy who has been strapped to a suicide bomb. He saves the boy’s life with some wire-cutters only for the defused ingrate to pick up a dropped assault rifle and gun down three of Porter’s comrades.

Disgraced and discharged for this lapse of judgement, Porter is left by his wife (played by Nicola Stephenson, Anna Friel’s erstwhile lesbian squeeze in Brookside), shunned by his teenage daughter, and soon growing his hair down below his collar. His former comrade (Andrew Lincoln – looking miscast as a military type), who is now suited and working high-up in intelligence in what looks like a set borrowed from Spooks, has found Porter a job as a security guard, but shuns him when he sees him. The scene is set for our downtrodden hero’s attempted atonement - a well-worn device in the genre since at least AEW Mason's 1902 imperial adventure The Four Feathers.

It’s now that Ryan’s plot takes some deep draughts of contrivance and coincidence as a TV reporter, who happens to be the daughter of a (fictional, obviously) minister in the Blair government that launched the 2003 invasion of Iraq, is kidnapped by insurgents, and Porter happens to recognise one of her captors on Sky News (where else) as being, yes, the lad who gunned down his three comrades all those sad, wasted years ago. He reckons he knows where the hostage is being held, and is soon begging to be “reactivated” and sent back to the Gulf.

As storytelling, Chris Ryan’s Strike Back seems thin and lightweight next to Richard Armitage’s other gig, Spooks. It’s not unexciting, in a sometimes laughable Boy's Own sort of way, but it’s not particularly interesting. Perhaps more intriguing is what it says about Sky1’s ambitions for its homegrown drama. This is the third adaptation of a popular author, after recent dramatisations of Terry Practchett and Martina Cole. All have been lavishly financed and surely it’s a good thing that Sky are starting to use the likes of Mercurio and Left Bank Pictures, the latter currently filming Sky’s next big drama, Mad Dogs, reuniting John Simm and Philip Glenister from Life on Mars and bravely not coming with the name of a bestselling author attached. Who knows (let’s be positive about this) - one day they may have the confidence to make something truly original.

In the meantime, it’s a fair bet that John Porter will find the girl, win back the esteem of his comrades and even gain the respect of his bolshie daughter. Being a former SAS soldier comes with a higher-than-average suicide risk attached, but Chris Ryan’s post-military career has been all about the very real possibility of happy endings.

• Pre-order Chris Ryan's Strike Back on Amazon
• Find Spooks on Amazon