It’s a Sin has been voted the Guardian’s best TV show of the year. Russell T Davies reveals why it took him 30 years to write, who the real Colin is – and why he just can’t keep away from Doctor Who

• The 50 best TV shows of 2021, No 1: It’s a Sin

Russell T Davies doesn’t hold back. If he’s thrilled, he shouts about it. And sure enough, the 6ft 6in giant of a man is shouting today. “I’m gobsmacked. I’ve never come first in this. Ever,” he exclaims, admitting that he has always had his eye on the Guardian’s list of the best TV of the year. “If I’ve had a show on, I spend every December watching that countdown wondering if I’ll be on it – I think A Very English Scandal got to No 2.” He’s right, it did. Three years on, his wonderful Channel 4 mini-series It’s a Sin has been voted the Guardian’s best TV show of the year. “I’m ridiculously thrilled,” says Davies, who is Zooming from his home in Manchester.

It’s 30 years since his first TV series – Dark Season, featuring a 15-year-old Kate Winslet – aired on the BBC. Since then, Davies has created any number of groundbreaking dramas (including Queer as Folk; Cucumber, Banana and Tofu; Years and Years) as well as breathing new life into Doctor Who. But he is particularly pleased to have won for It’s a Sin, the five-part drama about a group of young gay friends living – and dying – through the Aids era of the 80s and early 90s. This is the show he knew he had to write 30 years ago, and spent the intervening decades years putting off, because it was simply too personal and painful.