Well, no argument there. It’s now – brace yourself – 17 years since he solved his first crime, and after last year’s ruthlessly disappointing ‘The Clue of the Savant’s Thumb’ you, like Jonathan, might have been wondering whether his sedate deduction has a place on TV when people like Sherlock are gadding about, dynamically solving crimes while being young and sexy.

‘The Letters of Septimus Noone’ isn’t the ‘Classic Creek‘ of yesteryear, but it just about manages to prove there’s still a place for the show on our screens. Though you do wonder how much of the audience’s love of Creek these days is based on the nostalgia for the 1990s and those early brain-ticklers such as ‘House of Monkeys’ and ‘The Scented Room’.

Jonathan Creek is perhaps the only show that the audience is still willing to put on rose tinted glasses for before viewing.

The question of torches passing on to new generations is one that series creator/writer David Renwick isn’t shy about addressing and trying to dismiss, largely through wannabe sleuth and young David Tennant lookalike Ridley (a very fun Kieran Hodgson), in scenes that simultaneously mock Cumberbatch’s Sherlock and prove why Jonathan is still not yet ready for the scrapheap.

It does have the feel of a mothballed duffel coat mocking a fashionable Belstaff, except – Shock! Horror! – there’s no sight of the famous duffel. Of all the changes to make to Jonathan’s life – marriage, new home, corporate job, no more windmill (for budgetary reasons, sadly) – the exclusion of the iconic outerwear is the most inexplicably jarring puzzle.

Talking of puzzles, when it’s not fretting about its own age, the show has a few other brainteasers to ponder. None of them are as mentally taxing or audacious as in previous episodes especially as, in a surprising tweak to the formula, Renwick does a Columbo with Juno Pirelli’s locked room stabbing by showing you how it’s all done before Jonathan is brought in to solve it.

It’s an odd sensation, being one step ahead of Creek, and if anything it doesn’t help assuage the feeling that Jonathan is no longer needed in this bold new age of trendy crime-solvers. Surely, in part, we watch Jonathan Creek for that 30 minutes of mystery, in between the first act turn and the third act prestige, when any explanation from the audience on the sofa is possible? Or is Jonathan Creek so old now that it doesn’t have to prove anything with theatrics?

Alan Davies slips back into the title role more easily than he sits on a pony. As his wife Polly, Sarah Alexander brings a sprightly canter to an old dobbin of a show. If anything it’s the audience – especially those who weren’t wearing their rose-tinted glasses – who’ll have felt the most out of place.

Creek’s moved on, but not nearly as far as it thinks, and certainly not in the direction you might expect. Certainly not if you like duffel coats.

Aired at 9pm on Friday 28 February 2014 on BBC One.

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