Tony Law's long standing issues with alcohol abuse reached their peak in 2015, as the Canadian-born, London-based surrealist doubled down and brought cocaine into the mix. 'What a bad move!', he booms down the phone. 'Don't know why that didn't work.' Three years on, Law has adjusted to sobriety, and ahead of the 2018 Fringe believes his latest comedy hour, A Lost Show, is his best to date. 'It's about optimism and recovery,' he says, 'and I suppose, really deep down, it's about being given a second chance. Not just by the people you love but by comedy. And by an audience.'

Serious talk from a man who, ostensibly, is very silly. We shouldn't really be surprised, as Law is an articulate, sensitive human. His off-kilter stage presence and sense of humour is just the way he make sense of his life. In A Lost Show, Law uses comedy, in his own inimitable way, to relate to his darkest period and subsequent rebirth. 'I still believe in absurdity as a way of looking at the world,' he says. As a 15-year-old in Canada he had his life changed by comedy whilst at a party on a neighbouring farm. 'A video of Monty Python and The Holy Grail was on. I'd never seen anything like it! I watched it through the first time and I didn't even laugh, I was just staring at it and couldn't believe it was there. I watched it again and I was crying, it was so primal. It doesn't sound real or true, but it is. It opened up my feelings for the world and touched me deep inside.' He laughs heartily. 'A comedy about knights: it made me cry and weep with joy.'

Those taking their seats for A Lost Show shouldn't expect a straightforward narrative. Law is promising more of his trademark naughtiness, but points out that he's been 'seeing meaning in every silly joke' during the writing period, in which he's 'put way more effort into than ever before'. He talks of the influence of the music and art worlds, specifically the work of Pablo Picasso. 'I've always viewed shows like albums or a painting exhibition, and I view the jokes as a series of paintings; there's a feeling you get at the end and it's open to interpretation. I want everyone to come out at the end of the show and feel really positive, really happy, less daunted and not be able to pinpoint why,' he says, mischievously concluding that 'the people who get it will be the most intellectual.'

Law will also be running a shamanic healing workshop for comedians under the Giant Rhubarb at the Botanic Gardens for the duration of the Fringe, in the knowledge that the pressure and stress of performing on stage can drive people to depend on drink, drugs or both. That drinking culture, he's beginning to notice, is something that his younger peers in particular are shunning. 'They're learning so much more about life,' he says. 'One of the reasons why all the comedians I hang out with are so young is because there's a no-drinking thing going on. Adam Larter doesn't drink at all, he's never done drugs in his life. I used to think people like that were lame, but that's how lame I was.'

Being able to throw himself into a line of work where he feels genuinely appreciated and valued was, and continues to be, a blessing for Law, who relishes the prospect of driving the length of the country to have people laugh at – and frequently relate to – his art. The cathartic power of performance is one thing, but the support and strength of his family has been Law's saving grace: his kids, a wife who was willing to take him back if he showed the capacity for real change, his big black German Shepherd and his mother in law, who stepped in when he hit rock bottom.

'She put me up for the first six months', he says. 'Doing little chores like a wayward teenager gone out to the country: I did that when I was 45. "How's that kid doing? Well he's mended the fence". The only reason I'm not absolutely destitute and homeless is that I lucked out with family who give a shit about me. That kinda panic fuels my absurd show too.'

Tony Law: A Lost Show, Monkey Barrel, 2–26 Aug.