There seems to be something about romantic comedies in particular that captures people's attention. From William Shakespeare to Richard Curtis, audiences become engrossed with 'will they-won't they' storylines and 'love-hate' relationships where couples who have an obvious romantic chemistry struggle to express their feelings for many and varied reasons.

There are many great examples of this when it comes to sitcoms. We might think of To The Manor Born when, in 1981, the public's desire to find out whether Audrey fforbes-Hamilton would finally get together with Richard DeVere resulted in a viewing figure of 24 million people - a figure not surpassed by any other single sitcom episode until the Only Fools And Horses Christmas trilogy of 1996. More recent examples include Not Going Out and Gavin & Stacey. The latter also resulted in record viewing figures as it became the UK's most-watched scripted TV programme of the 2010s, and many are demanding for the series to return following its cliff-hanger ending.

Although it never achieved viewing figures of those levels, As Time Goes By remains one of the best examples of this sub-genre of sitcom. Airing on BBC1 from 1992 until 2005, its title and theme tune were inspired by the song of the same name which became famous after it was featured in the great romantic drama film Casablanca. The programme's original working title had been Winter With Flowers, but this was changed during the first day of filming due to protests by the cast.

Indeed, As Time Goes By was a more fitting title for a series that follows the relationship between two former young lovers - Jean Pargetter (Judi Dench) and Lionel Hardcastle (Geoffrey Palmer) - who meet unexpectedly after not seeing each other for 38 years. As with many great British sitcoms, right from the opening episode elements of tragedy are intertwined with comedy, as it is revealed that something as simple as a lost letter resulted in the deeply-in-love couple losing touch when he was posted to Korea as part of his National Service, in 1953.

In that first episode we learn that, after losing contact with Lionel, Jean fell in love with someone else and was happily married. From this marriage she has a grown-up daughter called Judith (Moira Brooker), although she has now been widowed for some time. Jean pioneered her own secretarial agency, proving herself to be a successful businesswoman, and she now resides in Holland Park in West London, the primary setting for the series.

After completing his National Service, Lionel moved to Kenya and ran a successful coffee plantation. Now back in London, he is publishing an autobiography (imaginatively titled My Life in Kenya) and so, in need of secretarial assistance to work through rewrites, he ends up unexpectedly reconnecting with his long-lost love. The theme throughout the sitcom's nine series is whether the couple, now in their sixties, will be able to rekindle their romance and live happily ever after. But there are also several other romantic storylines which emerge over the course of the show, most notably between Judith and Lionel's wealthy publisher, Alistair Deacon (Philip Bretherton). This fostered a feeling that the audience was watching a very realistic depiction of life; something more akin to a continuing drama, tuning in each week to find out what was happening in the lives of the characters.

As Time Goes By boasted a team of actors, writers and producers who were all highly experienced and talented. Geoffrey Palmer had already established himself as a great sitcom actor, having played Ben Parkinson in Butterflies and appearing regularly alongside Leonard Rossiter in The Rise And Fall Of Reginald Perrin. He also gave memorable one-off performances in Fawlty Towers and Blackadder. There was equally little doubt that Judi Dench was an accomplished actor, having played some of the most iconic Shakespearean characters on both stage and screen, and although she had less experience of television sitcoms, she had starred alongside her real-life husband Michael Williams in another romantic comedy, A Fine Romance. Palmer and Dench proved to have a natural connection that made the storyline believable, but the ease with which they were able to deliver their lines was enabled by the high quality of writing and production.

Although he was primarily known for his long-standing writing partnership with John Esmonde on successful sitcoms such as Please Sir!, The Good Life and Brush Strokes, Bob Larbey was increasingly looking to work on solo projects. A Fine Romance had been one such project and, although Jean Simmons was originally considered for the lead role in As Time Goes By, once Dench was cast Larbey was able to write scripts that played to her strengths.

The producer and director for all nine series was Sydney Lotterby who had worked on some of the best-known sitcoms of all time, including Last Of The Summer Wine, Yes Minister and Yes, Prime Minister, Porridge, The Liver Birds, and Up Pompeii!, to name just a handful. Significantly, he had also produced Esmonde & Larbey's Ever Decreasing Circles and Brush Strokes, meaning that he had worked with both the writer and Geoffrey Palmer before. The trust built up over the years through working together was reflected in the ease and family-like connections which the cast and crew had with each other both on and off screen.

The ensemble cast of characters also contributed hugely to the success of As Time Goes By. Alistair's youthful, energetic and optimistic outlook makes for a great comic contrast with Lionel: world-weary, often grumpy and pessimistic. Along with Judith and friend and colleague Sandy, he forms part of a trio representing a younger generation that Jean and Lionel often struggle to understand.

Sandy (Jenny Funnell) is also a significant character as she becomes ever more a second daughter to Jean as the series progresses and is involved in romantic storylines of her own. Other characters who make less frequent, but nonetheless important appearances, are Jean's sister-in-law Penny (Moyra Fraser) and her husband Stephen (Paul Chapman). Lionel's ageing but young at heart father 'Rocky' is played by Frank Middlemass, whilst his stepmother Madge is played by Carry On legend Joan Sims, who had previously appeared in another of Larbey's romantic sitcoms, On The Up (1990 - 1992). These characters are notably eccentric, acting as foils to Lionel's grumpiness and Jean's embarrassment, and are responsible for some of the finest comic moments throughout the series.

What is perhaps most significant about this cast and crew is that it remained consistent throughout the whole nine series run, this continuity being no small contributing factor to the programme's success. The production team were able to create detailed and believable backstories for the characters, seamlessly woven into the present narrative. Using pictures of Palmer's son and Dench's daughter in the opening credits to represent Jean and Lionel when they were younger helped establish the sense of realism and time, enabling viewers to buy into the story and feel that they too had known these characters for years and were therefore invested in what happened to them.

Structuring the whole series around one overarching storyline - meaning there will inevitably be recurring characters, themes and jokes - but also ensuring individual episodes are sufficiently self-contained is not easy to achieve but with touches like this and keen attention to detail, As Time Goes By did it effortlessly. For example, it is possible to laugh at references to Lionel being kicked by a mule whilst in Korea whether or not you heard the story originally told in Series 1. Such touches helped the series feel more like a continuing drama than a traditional sitcom.

Similarly, the show was allowed to grow and develop at what was a natural and believable pace. Lionel and Jean don't start living together until Series 3 and they finally marry in Series 4. It is in Series 7 we discover what happened to the love letter that had gone missing all those years before: rather poignantly, it had been on display in the Imperial War Museum; something Lionel had unknowingly made a joke about in the first episode. This is an example of how, from beginning, there was clearly a bigger vision for the series and much thought was being put into how it could develop longer-term.

Despite the obvious abilities of the cast and crew, the engaging storylines, domestic popularity and international success alike, As Time Goes By was regularly overlooked at major award ceremonies. The programme itself was never nominated at the BAFTAs and, although Dench had previously won for her performance in A Fine Romance, she was only ever nominated for As Time Goes By, losing out on the prize on both occasions. Perhaps, no matter how sophisticated the plotting or how much foresight was woven through the scripts, its gentle style of middle-class humour looked increasingly twee when compared with other programmes of the era, such as Drop The Dead Donkey, Father Ted, Absolutely Fabulous, I'm Alan Partridge and later The Royle Family - all of which did enjoy success at the BAFTAs during the 1990s - and were obviously more edgy as they sought to experiment with different styles of writing and filming.

The fact that As Time Goes By is currently repeated on the UKTV's Drama channel rather than Gold (the traditional home for repeats of classic British sitcoms) perhaps underlines both its overall gentler style of humour, and its dealing with sensitive topics; but it wasn't afraid of tackling edgier storylines. Indeed, the whole concept of falling in love later in life, post-divorce and post-widowhood, is itself a delicate subject and is why Jean initially hides her relationship with Lionel from her sister-in-law, Penny, wrestling with her love for both Lionel and her late husband. In turn, Lionel's own fears relate to a feeling of embarrassment that Jean is more financially secure than him and that he is not able to provide for them in this way. It is only when Lionel's father gives him his countryside home that Lionel feels able to propose marriage to Jean because he is "finally able to offer something proper, something real" to her.

Later in the sitcom's run we see Jean struggling to give up work and enjoy retirement because, for such a long time, work was the most important thing in her life, leaving her unsure how to cope without it. But it isn't just the struggles of the older generation that are explored: Judith already has two failed marriages when Series 1 begins and there is a constant feeling throughout that she has struggled to move out of her mother's shadow. She eventually enjoys an on-off relationship with Alistair, and they marry in the final series, aired in 2002. However, when the show was revived for two concluding specials three years later, they are seen struggling to have children. Exploring these issues, depicting the strains that couples can go through at different stages of their lives, is why As Time Goes By should not be underestimated and overlooked as a simple, quaint, middle-class sitcom.

There remains a strong affection for the series to this day, having come 29th in the BBC's major 2004 poll to name Britain's Best Sitcom, placing higher than any of Palmer and Dench's other shows. It is an example of what can be achieved when you have a winning combination of consistently tight scripts being delivered by actors who are at the top of their game.

Ultimately, the relatable realism woven throughout As Time Goes By explains its success. The audience related to the characters as they slowly and subtly navigated complex and emotive issues, all in the pursuit of true love. This also helped it become extremely popular in the USA, despite a key story arc being a satire on American television as Lionel attempts to write a mini-series for one of their major broadcasters. This demonstrates how engaging stories of romance are universally appealing and is why the fondness for the series will, like Jean and Lionel's love, continue to endure.