Since 2014, Reece Shearsmith and Steve Pemberton’s anthology series has had an audience disproportionate to its quality. We have had four series’ so far and still it’s a show largely unknown to the wider British audience. Yet, it’ remains a show which delivers some of the best half hours of television on offer.

There’s one limitation to the series, and that’s for each episode to take place in a setting related to the number nine (be it a house, train carriage or cubicle). A time slot of 30 minutes should also be a significant restriction but is why Inside No. 9 stands out. Within that half hour can be any genre with any character. While other shows need a couple of episodes to make an audience care for a person and their situation, Shearsmith and Pemberton can – and have to – do it in a few minutes.

Of course, some episodes require the investment more than others. This year’s more poignant offering was ‘Bernie Clifton’s Dressing Room’, portraying the broken down relationship of comedy double-act Cheese and Crackers, whose career and friendship broke down. Even before the big reveal, the episode is a journey through two people’s lives together and without each other, told through conversation interspersed with rehearsals of their old comedy routines. There’s humour in the mix but not so much that it downplays the unresolved tension between the pair.

Reece Shearsmith and Steve Pemberton in ‘Bernie Clifton’s Dressing Roon’

After that came ‘Once Removed’, a story told backwards. After the heartbreak of the previous episode, this was a welcome comedic turn. The story was told in segments, going back 10 minutes each time to reveal a new piece of the puzzle. In each part, our feelings towards the characters change as we know more about what they’re doing. It’s not a mystery in the traditional sense as we know the outcome, but plays with how we think we understand the world even when we don’t have all the facts.

‘To Have and to Hold’ had one of the darkest twists of the show but hid it within an episode highlighting the mundanity of marriage. The sucker punch reveal was amplified by the spending two-thirds of the episode feeling almost sorry for a couple going through the motions of life. If that episode was too dull for a viewer who could not hang around for the twist, that’s okay, there’s an episode written in iambic pentameter for the literature fans, a more horror-inspired episode and one which is more simple comedy. Then, of course, there’s the live Halloween episode.

With a series so varied by design, it has to be considered by its quality of writing. Here, everything is concise and well-considered. The characters feel well-rounded, as if we could guess what they’d be doing in their everyday lives despite barely knowing them.

As the episodes are so self-contained and the cast so limited and revolving, not a single character is wasted. Nobody is thrown in to be killed off or to deliver a throwaway line. It’s a strange feeling to watch a half hour show which was so entertaining yet not want more, lest it be spoilt. After every series, it becomes more infuriating that this is not more popular. Few other programmes can so easily transition between fun and thoughtful.