Spooks, BBC One

We first encountered Beth at sea, where she found herself sharing deck space with Section D's Heathcliffean operative, Lucas North (Richard Armitage). North had slipped aboard a container ship setting out from north Africa in order to assassinate the Somalian Al Qaeda chief Abib (Peter Bankole). Indeed, with silenced pistol at the ready, North was on the brink of completing his assignment when the ship was suddenly seized by Somalian pirates... or were they? Nope, they were an Al Qaeda cell planning something fiendish involving colossal quantities of explosives on British soil. Looked like the target would be the new aircraft carrier about to be launched in Plymouth with Her Maj preparing to crack the Veuve Cliquot across her bows. Wrong again! It was the Houses of Parliament, which the terrorists would reduce to rubble using a couple of state-of-the-art submersible speedboats, developed by some very creative south American drug smugglers. (Sophia Myles as Beth Bailey, pictured below.)

Abib and his comrades were a ruthless and trigger-happy bunch, and if it hadn't been for Ms Bailey's cool, analytical head and deadly marksmanship, Lucas would have been a dead man sinking. Yet for some reason he'd taken against Beth, who was working as a private security consultant, and so was less than amused when she successfully applied to join MI5. Could this by any chance be connected to the apparent revelation of Lucas's secret identity which was suddenly sprung on us in the closing moments, courtesy of the mysterious Vaughn Edwards (Iain Glen)? Friction ahead, shipmates.

It always raises a wry smile to note the way that Spooks storylines resemble a bunch of fairly recent newspaper headlines fed through a scriptwriting software program. There was even a wry reference to "our new Coalition" from the clubbable (but shrewd) new Home Secretary (Simon Russell Beale), who performed what may prove to be his most valuable service to the nation by tactfully shelving the resignation letter from chief spook Sir Harry Pearce (Peter Firth). The burden of guilt, secrets and deaths had finally become overwhelming for Harry after he'd felt forced to bump off the previous Home Secretary (Robert Glenister) with a bottle of "quaffable" but fatally poisonous Scotch, after the ex-Minister was exposed as a heinous traitor to the realm. Pearce observed his quarry's death throes with a grandiose theatrical dumb show worthy of Sir Donald Wolfit.

Firth can never be allowed to quit, because Spooks without Harry Pearce would be like Hamlet without its prince of Denmark. A character equipped with his own personalised antique dialogue ("I have been sufficiently ennobled..."), he treads the precarious line between gravitas and pastiche skilfully enough to allow the show to remain just the right side of farce. He feels like a lifeline stretching back to the reassuring certainties of the Cold War, which have now vanished in a fragmentary world of unreliable allegiances, shadowy splinter groups and ambiguous cyber-intelligence. It's no place for an old spook any longer, even if he has the dogged, dolorous Ruth Evershed (Nicola Walker) to lean on in his darker moments. She refuses to marry him though, which probably won't improve his mood in the long run.

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