How wrong she was: such was his stand-up performance at Edinburgh this year that Kay leapfrogged the newcomers' list to be nominated for the main Perrier Award. Not bad for someone who a year ago was checking ticket stubs at his local cinema.
In just two years (he kept the part-time ushering job for a while because he's a film fan), Kay has gone from spots in working men's clubs to devising and performing his own segment on BBC's live madcap Sunday Show, and Channel 4 has just signed him up to write a series on the strength of his send- up of fly-on-the-wall TV, The Services, which opens its series showcasing new comedy talent, Comedy Lab, tomorrow.
His manager, Lisa White, recalls discovering him nearly two years ago in a Manchester showcase. "I was blown away. For somebody so young, who had been doing comedy for only a few months, he was amazing. He has a worldliness and a knowingness way beyond his years."
Kay's rapid success, White thinks, may be attributable to his broad fame of reference. "Because so much is television-based, that means all audiences have a point of connection with him. I mean, he knows all about programmes I can barely remember."
A mark of that breadth of appeal is that Kay appeared earlier this month at the gay and lesbian Stonewall Equality Show - where he stormed them - and later in the month appears before the real Queen at the Royal Variety show. He doesn't yet know whether he will perform the same material.
But Kay, 25, of the cherubic looks and broad Bolton accent, puts his success down to luck, and says that he's still surprised by the speed of his ascent. "It's that Catholic guilt thing - I keep thinking it's going to end any day now."
He disarmingly says of his stage act, with its references to TV programmes, advertising jingles and dancing aunties: "I often think my act is really shallow. I look at other comedians and think, `Ooh, that's good. That's well thought out'."
Kay - who admits to an anorak tendency, evinced by his private collection of opening credits from TV programmes - has a televisual memory. Even his parents' break-up, when he was a teenager, is sourced through popular culture: "Half-way through an episode of Mork and Mindy, me Dad said, `I'm going.'"
Kay rejects the cliche of an entertainer who masks pain through comedy - "It wasn't that bad, really"- but admits that he learnt to protect himself from bullies by making them laugh. "They'd say I was fat, and I'd say, `I am, aren't I?' and then do jokes about it. It was my fault - I shouldn't have eaten so much."
He believes he is a born entertainer. He has report cards from infants' school which ask rhetorically why Peter insists on being the class clown. "I had discovered something I was good at," he says.
Unlike many comedians, Kay believes the art is not entirely instinctive. He must be one of the few comics to have studied telling jokes at university; his media performance studies at Salford included a module on stand-up. "I think you can learn stagecraft and timing, but you have to have something about you. My accent and the way I look help a lot. An American once said to me, `I have no idea what you were talking about, but you really made me laugh.'"
But even if Kay never planned his career - "I don't have a five-year plan or anything" - he appears to have long been a comedian in training; his pre-usher jobs included packing toilet rolls, and spells at Netto, Spar, a bingo hall and a cash and carry. All, he says, will turn up somewhere or other in the new Channel 4 series.
Kay has been described as a young Les Dawson - because "I'm fat and Northern" - but his childhood heroes were Julie Walters, Eric Morecambe and Ronnie Barker. Like Barker and Dawson, Kay is not averse to a bit of cross-dressing. In The Services, set in a Lancashire motorway service station, he plays all the characters, including its manageress and celebrity manque, Pearl. She, like all the participants, is savagely observed; like so many "ordinary" people followed by TV cameras, she has learnt how to play up to them while speaking in fatuous cliches. It is hilarious, one of the best pieces of comedy writing on TV all year.
Kay's empathy with women (he comes from a matriarchal Irish family) is evident. "I've always been able to write female characters - I find women funnier than men, and I love the rhythm of women's speech. I go to Slimmers' World, where it's mostly women, and I get so much material - they have no taboos about what they'll discuss."
Kay readily plunders colleagues' lives, too. "At the cinema I worked with two women called Marie and Pamela, and I would listen to them and just make notes. It was so good you couldn't make it up. One day Pamela was on the box office while Marie was changing the roller towel in the loo, so she said to a customer, `I'll tear your ticket here because Marie's upstairs changing her towel.' The chap looked disgusted and said, `That's more information than I needed, thank you.'"
Assiduous in his notetaking he may be, but it's not as though Kay has to go looking for material. "My mam went to the library the other day and the librarian said to her, `Your Peter's doing very well for himself, all that performing on stage and everything. Mind you, he's very quiet when he's in here.' I mean, I couldn't make that up, could I?" he says, laughing.
His ear for the details of everyday Northern dialogue led to one critic describing Kay as the next Alan Bennett, and brought him coachloads of pensioners at his next few gigs. "It's like we raided Age Concern."
Kay cites the North's rich linguistic and comedic seam as the reason why he will be buying a house in Bolton with his girlfriend next year, rather than move south to where much of his work now is. "I can only write about what I know. I'd be crap anywhere else."
`Comedy Lab: The Services', 11.30pm, Channel 4, 11 November