Jon Brittain is a busy man. We meet in a cafe opposite an old church he’s rehearsing Potted Sherlock in – he’s directing – between days of filming short sketches for a four-minute Channel 4 skit. It’s a week and a half before Brain of Brittain – a collection of old shorts and brand new things that come hot from the brain of Brittain. So it’s fair to say he’s got a lot on his mind.

Brain of Brittain started last year, when Jon “had a backlog of plays I wanted to finish – to get to the next draft. I need to immerse myself in them to get them finished.” That’s where Margaret Thatcher, Queen of Soho started out – as a 15 minute short, that was fleshed out to a full length, gloriously camp romp for the 503’s Christmas show, before delighting this year’s Fringe. The format gives Brittain a period of intensive development, and a chance to spring a menagerie of delights on a willing audience. He’s enthusiastic in praise of the form.

“Short plays allow you to find your voice – without splurging it on a full length you might not have the energy for – but there’s nothing to do with them afterwards.” Brittain reckons they help a writer develop their craft – “a lot of them are rubbish – but it clarifies what you like and what you’re good at.”

He’s also adept at producing or assisting with the production side of shows – a trait that helps. “If you have stuff you want to get on, and find a way to fund or subsidise it, producing it is a guaranteed way of getting it on – and it means it doesn’t get lost in development.”

Which can be frustrating. “You kind of want a yes/no answer when you send a play out – but the economics of the new writing scene mean that’s rarely what you get.” He’s quick to emphasise that he’s had absolutely brilliant support from Theatre503, as a former member of the 503 Five, and from New Diorama. And he doubts the show would have been commissioned the normal way – showing them it live was key to its further life.

Given the success of Margaret Thatcher there, and his tendency to self-produce, what does he make of the annual circus that is the Edinburgh Fringe?

“It can be the best thing in the world. But for Edinburgh, the show has to be ready in January – and you have to have confidence in it to know that it works – so many other things that will demand your attention.

“There’s nothing worse than selling something that you’re not completely behind or that came together too quickly. That’s really difficult, especially when you’re relying on that box office – when you have to put in that flyering time when you’re financially liable for a show you don’t believe in.”

“It’s not for everyone – but it was great for me – I had a great team.”

Brittain isn’t a writer with a five-year plan “I think part of it is my willingness not to plan, or not to stick to plans – if something seems fun, then that’s as good a reason as any for doing it.”

Initially he wanted to be a comedian, then an actor. He took a piece he’d written to NSDF – “I was expecting them to go – ‘Wow! You can act!’ and actually they went, “the writing’s good.” Carmel Winters at UEA gave him another nudge in the write direction.

After leaving UEA, he was unemployed and looking for a way in when, “my Mum called me up and said ‘I’ve noticed the Goldsmiths deadline is three months later than all the other MAs. I was seven hours late for the interview – I had a dole appointment written down wrong in my diary, I turned up and got absolutely grilled…”

“That was the making of me – a year where I could just think about writing.” It changed the way he looked at theatre, too. “For me, what it did was ask ‘what do you think theatre is? And then say no: it’s all of this. It’s everything, isn’t it? Everyone does stuff differently – and my interest in comedy and theatre and TV. My ethos now is to try and write plays only I could have written.”

There’s a pleasing symmetry that this Brain of Brittain is taking place at the New Diorama – where his first play, The Wake, was staged. He’s kept working with them – earlier this year, he acted in a short play about Julian Assange, and during that he popped the question about whether or not they’d like to host the next round of Brain of Brittain.

He says his career doesn’t make too much sense – a lot of what he describes has come from “saying yes to a stupid idea and it paying off in unexpected ways.” A lesson for many people trying to clamber into the arts: be governed by fun. For Brittain, it’s certainly working.

Brain of Brittain is playing at the New Diorama Theatre 15 December 2014