Lynn Ruth Miller loves comedy.

“Oh god, it’s gorgeous!” exclaims the Ohio-born funny woman who has been performing in the UK for the past six years.

 “I cannot recommend stand-up comedy highly enough. This is the best thing that ever happened to me.”

Sure, it’s hard making a buck, harder still to make the leap from the poorly paid open mic circuit to the big time. But Miller isn’t worried.

“I’m 86 and I have a pension,” she says. “When my career stalls I’ll be 6ft under.”

That isn’t a misprint: Lynn is 86 and didn’t take up comedy until she was 71. Her website describes her – fairly uncontroversially one assumes – as “the world’s oldest comedian”. Business is pretty good. As well as performing gigs up and down the country she has served as the compere at the finals of the Old Comedian of the Year competition at London’s Leicester Square Theatre.

“I’m having the best time. And I think I’m very funny so that comes across.”

The annual event is designed to recognise the talents of comedians over the age of 35 who have been toughing it out in the comedy trenches for at least five years without giving up their day job. That’s a crowded field, says Miller who describes the contestants – most of them in their forties and fifties – as “babies”.

“The competition gives hope to that big swathe of open mic people who are doing it just for the hell of it,” she says.

“These are the people who slog along getting £50 gigs in the boondocks and use £500 of petrol to get there. Who come home and tell their partner they still can’t afford groceries. We take these people who have been doing it forever and give them a chance to shine. It’s gorgeous.”

Miller has taken a few knocks of her own over the years. Twice divorced – “I don’t do a good job at marriage” – she lost her San Francisco home in the recent financial crisis. But her motto “I don’t believe in what ifs” has served her well.

Although she was a natural performer as a child, her route into comedy has been circuitous. She got a master’s degree in journalism from Stanford University at the age of 30 (she has a total of three degrees) and set out to become a crusading reporter with a byline in the New York Times. The reality proved more mundane.

“I never really made it big,” she says with cheerful candour. In 2003 she decided to enrol at a comedy college in San Francisco with the explicit aim of writing an article that exposed the tuition as “a load of crap” because “I figured you can’t teach comedy”.

The course instead exposed her talent (“I found I had a knack for it”) and she’s been telling gags ever since.

Young comics find it particularly tough if the audience doesn’t respond to their gags, she says.

Can anyone become a comedian? No, she says. “Some people just don’t have a sense of funny.”