Why did Back series 2 take so long to make? The unpredictable story of Channel 4's acclaimed sitcom

The initial obstacle to overcome was a scheduling headache, as producers were tasked with finding a six-week block in which the highly in-demand cast would be available to shoot.

By October 2019, executive producer Kenton Allen recalls that "all the planets aligned" and filming was due to begin, until a "terrifying" health scare for Webb brought everything to a halt.

The writer, actor and comedian had agreed to a medical check-up prior to filming, where he was informed by a GP that his heart was going to fail within two-to-six months.

Later diagnosed with a mitral valve prolapse, Webb required urgent life-saving heart surgery.

"That didn’t stop me doing a week’s filming for reasons that I now find inexplicable," the Peep Show star said at a virtual Q&A session.

"I just went to work for a week... I think there’s a scene where I’m supposed to be carrying a box up some stairs and the art department made it as light as possible, bless them.

"But I still found doing that scene the equivalent of five normal scenes and then I thought, really I should just go home, creep around downloading audio books and try not to have a heart attack."

Webb spent almost four months in recovery following his procedure, at which point he felt ready to return to work on the second series of Back, although initially feared his time away would show in the finished episodes.

He continued: “The continuity with my face is really interesting. I gather there’s wonderful things they can do in post[-production] to make my face more or less the same colour.

"But there are moments when I saw the rough edit where you go from me sort of bloated and pasty white and knowing that I’m about to have a heart attack, to when I’d had a large operation about four months ago and there’s quite a difference in pallor.”

Just when things seemed to be calming down, the team behind Back faced yet another earth-shattering crisis as the world became gripped by the coronavirus pandemic.

Filming was interrupted a second time to accommodate England's first national lockdown in March, resuming in the summer when restrictions had eased - but by that point, ordinary life was a thing of the past.

Co-star David Mitchell joked: "I’ve always seen the show as a historical drama set in a different time, so we had to wait for something to fundamentally change our era so it would seem like it was from a bygone time.

"Now, it’s set in the weird pre-COVID age you might dimly remember where people used to just walk up to each other for no reason like maniacs."

In the face of all this adversity, Back series two wrapped filming in September 2020, as confirmed by Webb in an image shared to Twitter featuring himself, his co-star Mitchell and director George Kane.

With the episodes now polished off and ready for broadcast, Back returns to Channel 4 later this month and - whatever happens next - the show will always have one extraordinary accomplishment to its name.

Executive producer Kenton Allen asked: “I don’t wish to put words in your mouth, Robert, but would it be true to say that Back saved your life?”

Webb responded: “Yes, in fact, you personally Kenton basically saved my life so I’ll be sending you some sort of token gift at some point.

He added: "The cast and crew sent me a lovely picture of them all standing outside in November [2019] shivering with a big sign saying ‘can’t wait to have you Back’ and that was one of the few times I actually cried during the whole rodeo.”

Back series 2 premieres on Channel 4 in January. Looking for something else to watch? Check out our TV Guide to see what's on tonight.