Once upon a time this was the best soap on television. Once upon a time it was the only programme of its kind to successfully mix improbability and wit and come up with endlessly entertaining drama. And once there were as many reasons as there were names in the cast list to set the video if you weren’t going to be around to catch one of its episodes.

Nowadays, though, Hollyoaks is but a bleached fossil of its previously wholesome, vivacious, living self. Amateurish, po-faced and pointless, its storylines seem to say nothing of consequence about anything in particular. Episodes blow up, blow over and blow out with ever-accelerating contrivance and corn. Everything that was so carefully and diligently put together during its groundbreaking early days has fallen apart.

The reasons are varied, but all have taken root during the last few years as the programme’s tally of characters and plots has climbed in tandem with the number of transmitted weekly episodes.

Take the cast itself. Hollyoaks has long embraced the mantra that gritty doesn’t have to mean ugly. But while the show’s present incarnation may be easy on the eye, it’s definitely not easy on the ear. The dialogue – its construction and execution – is probably the worst of any British soap on television today. Not only do the words its characters say bear little resemblance to the patterns and inflections of ordinary speech, but the delivery of the words has an equally long-lost relationship with reality.

In fact, rarely can there have been an instance of so many members of a single cast not knowing how to speak on screen. Dialogue is alternately shouted or muttered. Few actors appear to know how to open their mouths properly. Lines are bawled at inappropriately loud volume or tail off at the end into an incoherent mumble.

You could argue this is something of a virtue when considering sentences of the calibre of, “I need you so much and you’ve done this and I hate you – I HATE YOU!” or “Yer crazy! Just like yer murderin’ brother!” Admittedly even the most skilled of actors would have trouble imbuing such lines with even a semblance of dignity. Yet coherent dialogue, flawed or otherwise, must be the motor of any self-respecting recurring drama series, for fear of the entire enterprise grinding to an insurmountable halt and being blessed with the impression of going nowhere.

The show has never made any bones about its policy towards casting on looks first, experience second (though in the past the two seemed to be treated with equal reverence). Another curse of relying too much on the former, however, is the fact that even with the most sympathetic script and direction in the world, you can’t tolerate incompetence, or for that matter incompatibility, for that long.

Under both these auspices Hollyoaks has seen fit to shed dozens of cast during the last few years, and in the 12 months to date the turnover has reached epic proportions. One offshoot of this is that the show’s latest title sequence, an ugly 1980s-looking effort only introduced in late 2005, is already hopelessly out-of-date and full of characters who have either left or been killed off. It’s a problem that has plagued the series throughout its life by dint of the titles, right from day one, being a showcase for faces rather than atmosphere (Coronation Street) or location (EastEnders).

A second far more significant but no less recurring consequence is the impact upon the composition of the show’s stock of characters. Whenever a culling takes place in Hollyoaks it always atomises an already loosely-affiliated cast. The shedding of dead wood breaks up relationships, friendships and above all families, leaving behind an evermore disparate bunch of characters who have little in common and no cause to come into each other’s contact.

As such over the years the show has accumulated a ludicrous number of unrelated personalities for whom increasingly unlikely reasons must be invented for them to a) stay put and b) fall into the company of other remnants of broken families and hastily-concluded liaisons, regardless of respective past histories. This wasn’t such an issue when Hollyoaks first began; lately, however, it has driven a coach and horses through the show’s tried and tested tradition for concentrating on the fortunes of four or five core families.

This situation reached its extreme with the Morgans, a clan of six first introduced into the show in 1999 but who were sequentially and individually sent packing until only the youngest daughter remained, disobeying all natural instinct and logic by choosing to hang about on screen until Christmas 2005. Something similar has happened more recently with the Burton family.

One by one they have been shown the door until now only the son Justin survives, kept on presumably because his storyline, a clandestine relationship with his teacher, is proving popular with audiences.

Such practices have transformed Hollyoaks from a recognisable if exaggerated reflection of society into a desperately unlikely, near-cartoonish take on modern Britain. And the evisceration goes on. In this particular episode yet another family, the Ashworths, were shown divided and living apart thanks to a son’s indiscretion. Though even they cannot compete with the newest family of all, the Valentines, who went one better during their very first week on screen when their mum was run over.

Even the vocabulary of the show has been distorted out of all proportion. Once the programme was peopled with characters called Julie, Matt and Luke. Now the likes of Foz, Mercedes, John-Paul, Myra and Carmel walk the village streets, as if the production team have decided to start shooting a load of Eldorado scripts for want of anything better to do.

Hollyoaks has always painted life in ultra-broad strokes and rendered the most mundane of emotions in over-the-top jamborees of shagging and shouting. And it would be deluded in the extreme to deny the series has had something slightly preposterous about it from day one. But there used to be a sense that its absurdity was grounded in calculated irreverence. Storylines uncoiled with more than a hint of a purposeful raised eyebrow and knowing sleight-of-hand.

This whimsical implausibility has now been replaced by the plain implausible. There doesn’t seem to be any substantive motive or design underpinning the show’s relentless dramatic convulsions, not even one born of harmless self-deprecation. Things happen because they need to happen to fill up 22 minutes of airtime every weeknight. Things don’t happen because they make good television.

Such a state of affairs has handed the show a ghastly air of irrelevance, boosted further by the way it ditches plots and characters with such speed and disdain as to positively discourage dedicated viewing. Why bother investing in the show long-term, the production team seem to be implying, if we’re not investing anything in the long-term ourselves? Again, Hollyoaks has always been about programme-making on the fly – one of the reasons for its 11 years on air has been its low overheads – but not until the last few years has that virtuous expediency been expanded to incorporate the pursuit of the least worst option when it comes to telling a story.

In truth the show has never got over the demands of running five nights a week and the accompanying upheaval in personnel on and off screen, factors wholly related to the concurrent axing (in autumn 2003) of Mersey Television’s other Channel 4 soap, Brookside. Indeed, the person credited with writing this episode, Maurice Bessman, was one of several instantly transferred to Hollyoaks after years penning scripts for Brookside regardless of experience writing for a young audience or consideration of tone of voice.

His efforts tonight – an episode devoid of any humour whatsoever, no apparent logical structure (characters were seen in school then at home then back in school while other pupils never left a classroom) and one where everyone was arguing with each other – were sadly par for the course. There weren’t even appearances for any of the show’s dwindling band of veterans, upon whose shoulders so much of the responsibility for the programme’s survival now rests, and whose arrival in a scene can still occasionally give rise to flashes of the humour and energy of old.

“Enough is enough,” barked one character with singular appropriateness just before the credits rolled. “We’re leaving. Tomorrow!” So the revolving door turns again, spewing out more faces, washing up new ones, never ceasing its joyless work for fear that, were it ever to become stationery, the hinges would come off and the whole edifice would begin to crumble. But in truth that is already happening, and the door keeps on turning because it’s all its owners have ever known.