I know why projects such as The Invisibles exist. And in almost every respect, they exist for positive reasons. They exist because of civilisation. A certain amount of drama has to be made every year, the rationale goes. Why not, then, ensure the bit of drama you're making that year is a very civilised affair? Let other dramas bring together actors throwing 3am tantrums about “integrity”. Let differing ventures tackle scripts that redefine the nature of storytelling, after turning the writers into gibbering, bald alcoholics. Let Robin Hood get shot in a hedge in Hungary, in the sleet, 3,000 miles from the nearest Carluccio's.

Instead - like Kingdom, Doc Martin and Jam and Jerusalem before it - The Invisibles says to its all-star cast, in a very reasonable way: “Hey guys. Guys! We've all been in this business a long time. By any measure, we've earned our chops. Let's shoot something very simple, by the seaside, with nice, long lunch-breaks. How about Devon? Chilled chablis and seafood. I'll even write complimentary cashmere sweaters for everyone into the script.”

I totally understand it. As a great fan of almost any pleasant situation, I wholeheartedly applaud how very nice the whole thing must have been to make. There cannot be too much loveliness in this world. I'm all gung-ho for gorgeousness.

The only problem is, it's made a bloody awful drama. Really. In places, The Invisibles feels almost Eldorado - that unmistakable feeling that you should be watching it at 4pm, on ITV - and not, as in the case of both, wholly sober, on prime-time BBC One.

In a nutshell, Warren Clarke and Anthony Head are two former “high-class” burglars, who have just spent the past 20 years “going straight”, and turning very orange, in Spain. Returning to Britain, and a sleepy Devon fishing village, at the behest of Head's wife, Jenny Agutter, “the boys” find a reason to go back to their “old ways” within ten minutes. This then cues up a whole series of comedy-drama amusement, based around two OAPs pulling off “big jobs” while complaining about how much their backs hurt, how things used to be different in the old days, and how they'd love a sit down, a cup of tea and a Werther's etc.

Obviously, it could be quite amusing. But the whole thing trots along at a very odd pitch. The primary “Eh?”-prompter is their sidekick, Denzil from Only Fools and Horses (Paul Barber), who functions as the technical side of their operation. Indeed, such is the low effort of The Invisibles' script it's genuinely surprising that he isn't actually called “Techno”. He runs a bafflingly high-spec operation from his retirement villa at the edge of the village - sending encrypted police data to Head and Clarke's mobiles at the press of a button. Reception issues - such as the fact that, in every Devon fishing village I've been to, one has to stand on a bench merely to send a text, let alone upload video film from CTU in 24 - seem neither here nor there.

In addition to this, there comes the problem of Head. While Warren Clarke turns in a solid performance as some manner of loveable-but-dim sidekick - think John Prescott in a balaclava, crashing the getaway vehicle with the words “I only need my glasses when my eyes are tired!” - Head is a slightly ... less sturdy lead. Spending more than half his time engaged in angry Cockney shouting, saying plot-establishy things such as “We've 'ung up our boots! Forgeddit!”, Head unfortunately suffers from rampant, recurring Accent Slide.

At times, it becomes so acute he appears to be taking part in some manner of Accent Pentathlon - one that features the events “Angry Mitchell Brother”, “Someone a Bit Posh”, and “Anthony Newley, Slightly Pissed”. One wonders why the writers insisted he be an angry wideboy. The entire show wouldn't be affected one whit if they'd looked at the character synopses, crossed out “angry wideboy”, and written “Giles from Buffy” instead. Still, it adds another fact to humanity's sum total knowledge: Anthony Head cannot do angry Cockneys. We will know that for ever, now.

Alas, millions of people having to watch something as rubbish as The Invisibles is far too high a price to pay for this information. It is best that you let me shoulder this burden alone. In a civilisation, the needs of the many outweigh the needs of the few. We need to keep things pleasant.

The Invisibles, Thur, BBC One, 9pm

Editor's choice

• Proms Podcast with Danielle De Nisse
• The Bachchan tour is dynamite!
• Dark Knight storms to $155m record