Holby City has never been a drama to set the world ablaze but it has always been a solid, reliable soap.

Originally and very briefly, Holby City was a 50-minute drama, exactly the length of all BBC dramas and - if you take out the ad breaks - of all of ITV1's and Channel 4's too.

TV companies have experimented with shorter runs - Sky 1's new Crash Palace (Wednesday 10 October 2200 BST) is only half an hour - but the 50-minute show has become the lingua franca of television the world over.

Holby City is the full 60.

Mistake

It has happened with other series but apart from a mistake with Jonathan Creek, Holby was the first.

Early Jonathan Creek episodes were 60 minutes by mistake

The Creek mistake, according to its writer David Renwick is that he wrote 60-minute episodes and had a ferocious time trying to cut out 10 minutes in order for the show to be sold overseas.

Consequently, in Australia the first series of Jonathan Creek was thought of as a straight mystery rather than a romantic comedy because all the will they/won't they sparkle was cut out.

Renwick learned the lesson, he says, and from then on Creek was a 50-minute show.

But the BBC has a problem with this length because it often ends up with 10 minutes to fill between the end of a show and the beginning of the next.

That's why Points of View was invented, not as a vent for complaints against the BBC but as an easy filler to plug in the gap.

Unfortunately viewers could be tempted away more easily from that type of slight programme than from a major drama so Holby City was extended to take viewers right up to the (then) Nine O'Clock News.

It was actually a good thing, it meant that Holby was also able to grow its story a little more and not race to a conclusion.

BBC boss Mal Young has extended Holby City to at least 40 episodes

But that depended on it having a good story to start with and now, even though it no longer runs up to the news, Holby City is both continuing its 60-minute length and taking steps to run even longer.

Year-round

Not to go feature-length, but rather to go year-round.

There's been some back-pedalling on this idea lately; it was originally said that this new season of Holby would run for 50 weeks but now the official line is "at least 40 shows in the next 12 months".

The advantage to the BBC is that while it is expensive to make 40 episodes, it is hugely cheaper to do it than to make 40 episodes of different shows.

You use the same sets, same crew and same cast so what is called the slot cost drops: the money it takes to fill an hour with drama.

But that is only good for the BBC's bottom line budget, it has no automatic advantage to us as viewers and it does have a big potential risk that the series may not be able to produce the goods week in and week out.

Holby City has never been a drama to set the world ablaze but it has always done what it says on the tin and been a solid, reliable soap.

It just may not continue now that so much water has been added.