Most of the stuff out there didn't make me go, “Shit, I can’t do this,” except Little Night Music. I neither understand nor aspire to write music like Sondheim but I do understand and aspire to write lyrics that are that thorough. I think that’s probably how Sondheim works as a lyricist. I don’t think Elton has a process like Sondheim does or like I aspire to do because he’s not a lyricist and actually it’s the lyricist in me that makes me treat songwriting like a Sudoku. Not that you can tell because the sound system was so shit and we’re talking Broadway. I saw Billy Elliot which I think I can happily go on the record as saying, “The songs aren’t the best things about Billy Elliot.” I saw The Lion King the other day. The one I saw that scared me was A Little Night Music which, although it is probably not his greatest work, had “Send in the Clowns” which could be one of the great songs ever written. Before I wrote Matilda I hadn’t seen a musical for 10 years because I’d been too poor and then had babies and just lost that. There is no doubt he is one of those people you listen to. Sondheim - I saw Sweeney Todd in a school production once. I don't have a memory of hearing Lehrer and going “wow”. I knew the Elements song because a friend of mine learnt it and I knew “Poisoning Pigeons in the Park”. I certainly didn’t know Lehrer before I started doing this and have since gone back and checked him out. I always find it hard to deny influence because you bathe in everything. It’s the lyricist in me that makes me treat songwriting like a Sudoku Were you influenced in any way by Tom Lehrer or Stephen Sondheim? If the journey of the show doesn’t need that stopover then it goes. It is just a set of songs but my shows have an arc that I think about a lot. I haven’t played “Inflatable You” for three years, and it's my most popular song. I just dropped it in Montreal for the first time. We all know the rabbit was under the thing but I’m going to pull it out anyway.

But the long builds with the twist are very hard. And so I don't enjoy playing the songs which everyone knows so much, unless they’re “Dark Side” or “Rock’n’Roll Nerd” which don’t have a big twist and reveal, in which case let’s just enjoy them for their bits of wordplay and fun music. But they want to hear this song and I always say, “I’m glad you want to hear it,” but unless the moment you hear “Only a ginger.” undoes the assumption of the previous two and a half minutes that we’re talking about the N word, it’s dead to me. I’ve worked really hard to keep the newer stuff off YouTube. “Prejudice”, the ginger song, which is a play on acronym - I’ve been in the States where my fans are more weird and rabid YouTube bingers. Having said that, I’m much happier if people haven’t heard it.

I’m conscious of where I have an advantage over stand-ups, which is they do bear a second hearing. Are you conscious that your songs have a lifetime? JASPER REES: Your trick is to have people wait for the gag with eager anticipation even if they’ve heard it before. You watch how much McIntyre uses his hands. Luckily my persona is a bit odd so it doesn’t matter. Long before it became a rock‘n’roll thing I was wearing theatre amounts of make-up. Along with the ultrabrite grin, the make-up helps him telegraph his ineffably sweet charisma to the cheap seats. Instead of kohl, his eyes are rimmed by thick black specs. He is as usual shoeless, strawberry-blond scarecrow hair all over the shop. The joke about Minchin’s lashing tongue is that he is of course all twinkly civility. Where a regular stand-up would look horribly petulant to bear a grudge, Minchin put his toxic riposte in song. He made his Edinburgh Fringe debut in 2005, to be greeted by a ripsnorting review in The Guardian. Only when he twigged that his rare gift was for singing and joking at the same time - “comic songs is probably what I’m best at” - did a butterfly shuck its chrysalis. His casually brilliant pianism is married to Sondheimian lyrical dexterity. He moved to Melbourne and became creatively paralysed, spending three agentless years playing in a covers band in an ersatz English pub. As he tells theartsdesk, Perth taught him the straight-and-narrow virtue as a bit-part actor-composer-bandleader that “you have to work and work and work and work to get the lowliest of jobs or exposure because there’s three gigs and one theatre company or two at a pinch”. The journey from Perth, where he spent his first 26 years, to global comedy stardom has been winding. And en route he hosted an inaugural Comedy Prom at the end of a week of riots which will not be forgotten by anyone who was there. The marriage between Matilda’s naughtiness and Minchin’s back-of-the-class anti-authoritian instincts was a five-star hit which moves this month from Stratford-upon-Avon to the West End.

Tim minchin