The unforgettable Caroline Aherne began her career on the Manchester comedy circuit, where she started out as a stand-up comedian. Although she did occasionally perform the odd routine as herself, she was always primarily a character actor.

It was on these small stages in local comedy clubs that she honed her craft. Characters born out of her early period of stage performance included: Sister Mary Immaculate (a reference to her middle name and Irish roots) and Mitzi Goldberg (the lead singer of the country and western act, The Mitzi Goldberg Experience). But it was with the help of Frank Sidebottom that she unleashed her most potent and perhaps most celebrated character, the ineffable Mrs Merton.

The character debuted during Sidebottom's show on Piccadilly Radio, where Caroline had been working as a receptionist. Aherne would then later appear on Frank Sidebottom's 5/9/88 album, and again in his Yorkshire Television series, Frank's Fantastic Shed Show (with the character then going under the name 'Mrs Murton').

In many of her first major TV appearances, Caroline continued to appear in the guise of the character, donned with little more than a grey wig and glasses - she was afforded no such luxuries as prosthetic make-up to disguise her obvious youth. Yet, despite this, she was able to slip so convincingly into the character of the gently abrasive old woman that it seemed to matter very little to audiences.

In 1990 Mrs Merton got her first big break - a regular slot on Granada TV's topical television-based debate show, Upfront. The series was a sort of Question Time meets Points Of View, and while an opinionated audience in an environment such as that could be seen as a comedian's worst nightmare, one thing was clear against the hubbub of the debate - audiences were reacting positively to Mrs Merton and her monologues which punctuated the show.

The next step was obvious. Having proved her worth, the character was given a showcase for Yorkshire Television, Mrs Murton's Nightcap. It was a one- off unbroadcast pilot, which seemed to be intended to lead Aherne down the path of comedy chat show host. The blueprint for this pilot was clearly developed with the character's success at handling audience participation in mind.

When the Mrs Murton's Nightcap episode was finally dug out of the archives and released into the public domain, we saw a decidedly different style to this incarnation of Mrs Merton, as she welcomed Chris Donald, Liz Kershaw and Andy Kershaw into her living room. The potential was there, yet this pilot failed to get off the ground. It was a setback for Caroline, but where a lot of people may have considered dropping the character altogether and trying something new, she remained undeterred, she knew that this was a character worth pursuing.

And so it was, that Mrs Merton made a triumphant return when a second pilot was recorded a couple of years later, in 1993 for Granada Television. Originally called That Nice Mrs Merton, then later renamed, this time it was commissioned.

Featuring the writing talents of Craig Cash, Dave Gorman, Henry Normal and Caroline Aherne herself, The Mrs Merton Show was very similar to the pilots that preceded it. It was a character-based chat show which interviewed real celebrities. It took its lead from The Dame Edna Experience before it, which was a huge hit for ITV in the late eighties and was among the first to popularise the genre.

Now fully realised with a twinset and pearls, Mrs Merton blossomed, and in the very first episode (broadcast February 10th 1995) we witnessed the iconic moment that ended up defining the series, a question targeted at Debbie McGee:

So, what first attracted you to the millionaire Paul Daniels?

Mrs Merton grew in popularity and, as a result, Caroline's star ascended. After two series on BBC Two, Mrs Merton took her table, chairs and little red sofas and moved them to BBC One - this was a prime-time promotion that coincided with a run of British Gas Adverts.

The 1996 run of commercials not only cemented Caroline Aherne as a household name, they also officially introduced us to a new aspect of Mrs Merton's character, as the doting mother of her son, Malcolm, played by Craig Cash.

Her offspring was by no means a new invention; Mrs Merton would frequently mention 'my son Malcolm' in The Mrs Merton Show, and he did actually appear twice over the course of the series. However, it was these adverts that were crucial; they cemented the pair as a kind of double act, and if these commercials did not directly inspire the sitcom that eventually followed, then they certainly gave fans a clue as to where the character was heading next.

However, all that would have to wait until Caroline Aherne and Craig Cash finished another project they had been working on ...

Their next project was something of a low-key affair, filmed in 16 mm film using single camera techniques. It was a production that allegedly had to fight tooth and nail not to include audience laughter; the producer, Glenn Wilhide is on record as saying, "It was a big fight to make sure it had no laugh track". In today's comedy climate it is hard to believe that in 1998 this was such a hard-fought battle. However, the argument was won and as such we followed the lives of the Royles - a normal working-class family, living in a small council house with only the sounds of their television set (and occasionally Jim's banjo and a little bit of Mambo No. 5) as an accompaniment to their exchanges. The conversations were based around the ordinary everyday chat that every family up and down Britain might have, such as 'What did you have for your tea, Dave?'.

Their lives contained none of the heightened reality we would normally expect from a sitcom, or indeed any other scripted show on television, and in many ways that was the key to its success.

The first series of The Royle Family was something of a hit, debuting to great reviews from the press. The biggest critic of the series was, surprisingly enough, Caroline herself. After seeing the first episode back, she was reportedly so unhappy with it that she didn't want the episode aired. So strong were her feelings that she dramatically tried to buy back the rights to the series. Fortunately for everyone, it was more than she could afford, at almost a quarter of a million pounds. "I'd have bought it from them, if it had been any less though", she later admitted.

Aherne's struggles with her mental health are well known, but the extent to which she often doubted her own projects isn't perhaps as widely understood. However, any artist may suffer doubts, and it was ultimately still early days for the series.

Tucked away on BBC Two, The Royle Family quietly announced itself to the world, and was not immediately recognised as one of the all-time great sitcoms - it certainly wasn't a cause for Caroline Aherne and the team to abandon Mrs Merton (who at that time was still their strongest asset). So, they turned their attention back to the character for a BBC One sitcom, Mrs Merton & Malcolm, which took Mrs Merton out of her chat show environment and into her home - a suburban 1950s time warp with her overgrown son, Malcolm (Craig Cash again); a bedbound and mute husband; and the occasional visitor to keep them company (which was almost always Arthur Capstick, played by Brian Murphy).

The episodes were written by Caroline Aherne, Craig Cash and Henry Normal (all of whom had developed both The Mrs Merton Show and The Royle Family). The original intention was to create a fairly light-hearted, pre-watershed sitcom, but somehow Mrs Merton & Malcolm came out as a black comedy, and this was what really set the show apart and ultimately made the sitcom something of a bone of contention.

Was a slightly ominous tone intentional? That became the question on everybody's lips. Despite the cheery nature of Mrs Merton, without an audience, celebrities to grill, or an exciting new energy saving tariff to sell, you cannot help but feel a certain bleakness, an underlying tragedy to the character's situation, as Mrs Merton treats her adult son like a child. We see her wake him up with glee on the morning of his 37th birthday to do his 'height measure' against their kitchen door frame, only to discover that his stature certainly seems to have plateaued in the more recent decades.

This new direction for Mrs Merton was by no means a bad thing; comedians were really pushing the boundaries of what comedy could do and how far it could go in the late nineties. Chris Morris's Brass Eye is the most obvious example, but we also saw it with Rob Brydon and Julia Davis's Human Remains (another Henry Normal production) and you can't mention twisted nineties comedies without talking about The League Of Gentlemen.

It was The Office (that arrived a little later in 2001) that came to be credited with really breaking the glass ceiling. It made losing the laughter track the norm and with its own cynical and slightly bleak style of comedy it is widely considered to be the sitcom that changed the landscape forever. Yet critics who only saw Mrs Merton as the Dame Edna-esque chat show host were not geared up for what appeared to be a new edgier angle on the character and the shift of tone wasn't popular.

With Mrs Merton's husband silent, confined to his room and only glimpsed as a lump in bed, before he died in the final episode, the series could not help but take on a sinister edge. However, it was Malcolm in particular that came in for a great deal of criticism, critics labelled his childlike behaviour 'odd'. It was Time Out Magazine that branded the series 'possibly the most disturbing show on television' and this negative feedback floored the writers.

Malcolm's infantile behaviour (such as playing musical statues at his sparsely attended birthday party) was obviously intended to follow in the footsteps of the likes of Dougal from Father Ted, or Mr Bean, both popular nineties comedy characters who were stuck as perpetual children.

There's a definite argument that of all the sitcom protagonists you could describe as tragic (a list that would run into the hundreds), Mr Bean was one of the most tragic, living alone as he did with his teddy bear. Seemingly pulling on the popularity of these iconic characters, a similar vein of sadness runs through the first episode, as we see Malcolm wait for his birthday party guests that we feel certain will never arrive. The only true friend the pair seems to have is the aforementioned Arthur Capstick.

The character's visits were the real highlight of the show. A considered and understated performer, Brian Murphy caught the nuance of a slightly fuddled but kindly old man perfectly, just as Liz Smith had achieved with Nana in The Royle Family. He contributes to some of the best scenes in the show, one of which arrives in the final episode, when, after the funeral of Mrs Merton's husband, the Vicar (Steve Coogan) drops by prompting Malcolm to put on his late father's favourite record, an old Glenn Miller jazz tune. As the record plays, toes start tapping, and as Mrs Merton becomes overwhelmed and starts crying, pulling a handkerchief from her sleeve, her guests start surreptitiously acting out a full jazz quartet, culminating in a final bizarre chorus from everybody of Pennsylvania 6-5000. It's a genius scene, an absolute masterclass in surreal comedy.

While not a critical darling, the programme was still a hit with audiences. An estimated 7 million people tuned in for each episode over the course of the series. The 'Macarena scene' in particular, became the most famous moment of the run, as the duo performed the impromptu dance at the kitchen sink wearing marigolds. As a writing team, Caroline and Craig always had a flair for inserting a well-placed dance routine.

The BBC remained committed to the comedy; a Christmas special was already in development when the first series aired. However, the bad press had knocked all confidence out of Caroline and Craig, as they began to doubt the entire concept of the series. Talking about the show back in 1999, whilst the series was still airing, Craig Cash said:

"We've been accused of all sorts, from incest to insanity. Even some of the people who like it say, 'It's fantastic, it's so dark'. But we honestly didn't mean it to be. We didn't think there was anything offensive about it. Kids seem to love it, I'm glad to say. They see it for what we intended."

He then added that they took the decision to cancel the Christmas Special: "We wouldn't want to put people off their Christmas dinner", he joked.

Aherne and Cash preceded to focus on the second series of The Royle Family instead, and in doing so, they made one of the most beloved British comedies of all time. With Caroline now fully committed to the series, they never looked back.

The late great Caroline Aherne, who left us far too soon, may ultimately have doubted and maybe even regretted Mrs Merton & Malcolm as a spin-off to her wildly successful talk show. It is perhaps in line with Caroline and Craig's wishes that the series is rarely mentioned and never repeated. Yet, it proved that Mrs Merton was an enduring character. Much as she had almost by chance stumbled into the role of chat show host, she stumbled just as suddenly into the role of sitcom protagonist, and in doing so evolved as a character much like Alan Partridge.

The programme may have come out a little darker and more offbeat than the team's original intent, but that certainly didn't mean it wasn't a great piece of comedy, bleak or otherwise. As to whether Mrs Merton & Malcolm truly is a light-hearted sitcom about an overbearing mother (in the style of Ronnie Corbett's Sorry!) or a slightly sinister comedy drama (perhaps presenting an early peek Inside No. 9) is up to you, and that in itself makes it one of the more fascinating sitcoms of the last twenty plus years, and ultimately a worthy part of Caroline Aherne's enduring legacy.