If things had turned out differently Nick Helm could be shambling around St Albans right now, etching genitalia onto the sides of cars.

Instead the 33-year-old is finding fame in BBC3’s hit show Uncle, as out of work musician Andy – who shambles around etching genitalia onto the sides of cars.

“I am pretty badly behaved in the series,“ says the bearded funnyman.

“If I could draw a penis on the side of someone’s car with no consequences that’s how I would live my life. So there is a bit of wish fulfilment to it.“

He discovered his love of performing at Sandringham School and has had some success on the stand-up circuit, performing on Russell Kane’s Live at The Electric and appearing on 8 Out of 10 Cats.

But, he admits, it has been a tough slog. “There was a period about four or five years ago that if things hadn’t started taking off then I would be like Andy is now.“

Luckily success came knocking for the former Cunningham Hill pupil after he won Dave’s Best Joke, 2011 at the Edinburgh Fringe and he was asked to do some online videos for Channel 4.

He says his casting in the comedy series, about an uncle on the brink of suicide who is forced to look after his 12-year-old neurotic nephew, consisted of a chat with the director and was “the easiest thing that’s ever happened.

“Well apart from the years of doing Edinburgh, having no money and starving beforehand.“ So is he similar to Andy, a man whoes idea of encouragement at a kiddies’ football match is to shout ’stop being so s**t’?

“No. F**k off. I’m not like him in real life.

“There are some aspects that are similar (such as the swearing, clearly), but I did everything off my own back. I did data entry and bar work to get enough money to do Edinburgh and put on my own shows. I did it hoping it would pay off one day.“

But the Stockwell resident says he is by no means famous yet.

“I’m not a star,“ he says. “I did a gig last night where no one had even heard of me.

“I’ve been recognised once or twice on the Tube and luckily people like the show. If people had absolutely hated it, it would have been a nightmare.“

Filming for the six-part series was done last autumn in Croydon with Nick penning comedy songs to perform with his young co-star.

He isn’t an uncle or dad in real life and says of working with a small person: “Kids, I don’t really have much contact with them. There’s not a legal reason for that. I spend most of my time trying to entertain drunk adults and that’s a bit like babysitting.

“The scariest thing is the kid who is Errol in the show (Elliot Speller-Gillott) is really talented and a child actor, and out of the two of us he is the veteran and knows what he’s doing.

“So many scenes we were in he was much, much better than me, but he’s 12!“ He adds: “On paper there’s not a lot to like about Andy. He manipulates everyone and there’s a long list of his bad points, but that’s what makes the show work. His relationship with his nephew brings out his better qualities.“

Nick says St Albans will “always be home“, but he’s in no rush to settle back here with his own brood of rugrats.

“I’ll have them one day, but I’ve only just started getting paid. I’m not scared of kids, well some are scary, but you have got to be in the right mood for kids and then that’s got to last for about 30 years.“

Uncle is on BBC3 on Monday at 10pm