Last Night's TV - Spooks, BBC1; Bouquet of Barbed Wire, ITV1; Coronation Street, ITV1

Hurrah, Spooks is back. In my case, however, it is a slightly muted, self-conscious hurrah, because before I watched last night's episode, I had never seen a second of Spooks. Nothing. Not a sausage. Not that I suppose sausages have ever played much of a role in Spooks, but I can't be certain. Maybe there's been an exploding toad-in-the-hole.

Now, I'm aware that television critics, who need all the credibility they can muster, should be a little circumspect about declaring their ignorance of a hugely popular series. Even the splendidly waspish A A Gill, who normally doesn't seem to mind who he offends, was uncharacteristically apologetic the other day in admitting that he has never sat through an episode of Coronation Street. And my friend Hunter Davies won't mind me telling you that back in the Nineties, the grand panjandrum of Associated Newspapers, Sir David English, ordered his termination as TV critic of the Mail on Sunday after he coughed up in print to having pursued an EastEnders-free existence.

Mindful of that, I wondered whether to review the first episode of the ninth series of Spooks – the ninth series! – feigning a degree of familiarity. But I quickly realised that all you Spooks regulars would see right through me in no time. I'd be the MI5 undercover operative wearing a Groucho Marx mask, deceiving nobody. So I thought I'd better come clean.

Anyway, the good news is that I can see what all the fuss is about. Last night's episode started brilliantly, with angst-ridden spymaster Sir Harry Pearce (Peter Firth) taking it upon himself to bump off the former Home Secretary, who it turned out had been complicit in the death of Ros Myers (Hermione Norris). I can't imagine that this is how it works in real life, Dame Eliza Manningham-Buller or whoever getting her hands dirty with a spot of garrotting, or even with a spot of deadly poison in a bottle of 30-year-old malt whisky, which was Sir Harry's modus operandi, but it was a terrific scene and made fans of my wife, a fellow Spooks novice, and me from the off.

There followed a complicated storyline involving an al-Qa'ida plot to blow up the Houses of Parliament with a couple of dolphin-shaped underwater missiles. This was masterminded by a teenage girl doing her dastardly planning on a computer in her bedroom in a London suburb, so don't be thinking that they're all just talking to their mates on Facebook. Actually, the entire episode, and no doubt all eight previous series, required a sustained suspension of disbelief, but it was very slickly done, with a few smart nods to reality. Neatly, the new Home Secretary (Simon Russell Beale, no less) talked about being part of the coalition government.

He also said that "everything in life is about timing, from sex to the golf swing" and I couldn't agree more, which brings me to my own flawed timing, in that I finally started watching Spooks just as Hermione Norris's character, Ros, was buried in a country churchyard. Ros might yet be magically resurrected, which I gather has happened before, but on the assumption that she really was blown to kingdom come at the end of series eight, I have to record a small personal irony, Norris being one of my favourite small-screen actresses.

It's not so much that she is lovely to look at and all the sexier for often seeming just a little bit repressed, more that she really is very good at acting – not that she ever gets cast as women who couldn't conceivably also be called Hermione. And so to the final episode of Bouquet of Barbed Wire, in which Norris's character, Cassandra, could just as easily have been a Hermione. This is a drama I have resolutely championed on this page as nigh-on unmissable, but it is with a heavy heart that I confess to giggling most of the way through the denouement.

Those of us who come from the 1970s are understandably wary when TV executives sanction remakes of programmes that practically defined our lives back in the kipper-tie decade; indeed, there have been few worse crimes against nostalgia than Reeves and Mortimer in Randall & Hopkirk (Deceased). I was worried that the same might apply to Bouquet of Barbed Wire, but was cheerfully reassured by the first two-thirds of the thing, which brought Andrea Newman's cauldron of warped sexual mores nicely to the boil for the 21st century.

Last night, regrettably, it bubbled right over. Everything went so far over the top – the writing, the acting, even the score – that it began to look like a spoof, and when Peter Manson (Trevor Eve), finally driven bonkers by the wholesale destruction of his apparently successful life, took his last-act swallow-dive out of a hot-air balloon, I'm afraid I could no longer suppress the tears. I haven't laughed so hard at the telly since Larry David tried to prise a golf club away from a corpse in Curb Your Enthusiasm.

The mistake, I think, was cramming it all into three episodes. The original ran for two series, which allowed room for the misery to develop properly. Consider poor Gail McIntyre (Helen Worth, another small-screen favourite of mine) in Coronation Street. Last night she learnt that her son Nick's new fiancée is only pretending to be pregnant, the very least in a series of terrible trials, which include giving birth to one psychopath and marrying another, that Gail has endured since arriving in Weatherfield. But her suffering has lasted since 1974. These things need time.