Spooks will be sadly missed in my house

Spooks

(BBC1)

There is a running joke in our house – just before I settle down to watch Spooks on Sunday night the wife will take a sarcastic guess at the about-to-unfold storyline, writes David Briggs.

"Let me think," she always says, "terrorists will hide a bomb in London somewhere and some dodgy Russian will do some whispering."

She then waltzes out of the room and heads off for a bath.

Having been a fan of the BBC's M15 drama for the last 10 years I choose to ignore these comments but have to admit being rather glad that this is the final series for Section D chief Sir Harry Pearce (Peter Firth) and his ever-changing band of spies.

By the end of the previous series the plots were becoming rather predictable and I did begin to wonder if Harry was quite the legend that the rest of M15, the CIA and Government seem to think he is, judging by the number of his staff who have been killed or sent loony while working for him over the last decade.

There was an increasing focus on gadgets and high-tech wizardry at the expense of good old-fashioned espionage and double dealings.

It felt like a programme that had gone on just that little bit too long.

However, the first three episodes of this final six-episode series have proved gripping viewing so far and seem to be building nicely to a rip-roaring crescendo.

The focus of the series is very much on Harry and his past as a spy during the Cold War.

His former Russian opposite number in the KGB Ilya Gavrick (Jonathan Hyde) is now a Russian foreign ambassador and is in town to do business with our own government.

He brought with him his wife, Elena (Alice Krige) who spied for Harry back in the day and had his son, Sasha (Tom Weston-Jones) after an affair. Sasha now works in the Russian secret service and has uncovered his mother's duplicitous past.

Sasha has become embroiled with Harry as they try to keep Elena's past hidden.

Oh, and by the way, Sasha doesn't know Harry is his father!

Last night's episode saw Harry and the team realise the Americans are trying to disrupt the deal between Gavrick and the Brits and it was the CIA behind an assassination attempt on Gavrick in episode 1 and the theft of M15 secrets and murder of Harry's tech guy Tariq in episode 2.

The old order of enemies and friends is getting ever muddier.

Meanwhile Section D were dealing with an anarchist suspected of bringing a dirty bomb to London (don't tell the wife).

The writers' decision to look back to the Cold War for their grand finale has been an inspired one – returning the series to what has always made it enjoyable – espionage, double agents and out-of-the-blue twists.

Of course the Cold War plot, coming as it does just as Tinker Tailor Soldier Spy is in our cinemas, means the series has drawn comparisons (mostly unfavourably) with John le Carre's seminal spy novel.

But these comparisons are unfair – Spooks is not meant to be a serious portrayal of M15 – it is prime-time television entertainment and, while I think it right that it draws to a close now, I will miss it.