There’s a great moment in the final episode in the 20th series of Silent Witness (I typed “Witless” then, a Freudian slip). Anguished pathologist superhero Jack wails at his daft colleague Nikki, who’s yet again put herself smack in the middle lane of the Danger Highway: “This has got nothing to do with us! It’s not your job! Maybe we are making this worse!”

Hallelujah! At last, the fundamental weekly idiocy at the heart of Silent Witness is revealed, recognised and held up to the light.

Every week, in every episode, the team wades around in crime-puddles that are none of their business. Now, I know that it’s a series that’s been going, as I said, for 20 years and it is a big BBC1 cornerstone, a huge Easter Island statue of a drama that routinely draws well over six million viewers.

Even I’ve been known to watch it outside of work, just because it’s on and I’m a reluctant abductee to its crazy world where pathologists solve crimes, interview suspects and tell the police absolutely everything they need to know.

But after 20 years… come on, give it a rest. It’s time Silent Witness was silenced for good. There’s really no need to bring it back for a 21st series. It’s too silly to live. It’s exhausted what was once a rich seam of mortuary-slab stories that should stay there, in the mortuary, but which leak into the outside world as the pathologists use their special powers of investigation.

I’m prepared to admit that it’s possibly only me that’s bothered by the crime-busting aspect of Silent Witness, where the cops routinely stop to pick up a pathologist as they blue-light their way to arresting a suspect.

You should see the look of weary, battered resignation on the face of my colleague David Butcher when I hop aboard my Silent Witness monorail, yelling, “Pathologists don’t investigate crimes!” as I thump the desk with my ballet slipper like a TV critic Khrushchev.

Typically in one story in this current series Jack and Nikki were running around a London railway station with a load of police officers looking for a murder suspect. Why? They are pathologists. No one was dead. There’s absolutely no need for them to hurtle around the capital’s public transport system chasing criminals.

That’s what the police are for, even the comedy-police routinely recruited by Silent Witness, the lunks who will do anything for a quiet life, who are blinkered and unimaginative, who sit in the Lyell Centre, here an adjunct to Scotland Yard, being lectured by a handful of infallible scientists.

Tuesday’s last episode is the epitome of torrid weariness. Jack and Nikki are in Mexico, investigating deaths and kidnappings that have nothing to do with them (see Jack’s plea above). It’s an episodic, all-over-the-place hour of overblown nonsense that even has the cheek to end with a 20th birthday congratulatory message on the closing credits. Blow out your own candles, why don’t you?

Emilia Fox as Dr Nikki Alexander 

The wider point here is that BBC drama has become so big and bold of late – the bonkers Taboo doing really well at prime time on Saturdays, Line of Duty (with its proper police interviews – hooray!), Happy Valley, and the current Apple Tree Yard, which is sexy and fearless in its way.

BBC drama can afford to be just as daring in what it wipes from the slate, and axe a 20-year-old drama that’s long looked frayed around the edges. Of course there will be protests but everyone will get over it.

We are currently living in an age of some of the most thrilling dramas that I can remember, so let’s shut the mortuary door on Silent Witness for the last time.