I’d sing “My Old Man Said Follow the Van”, followed by Handel’s Messiah, and not think anything about it. Then my father would write me a poem, and my mother would play some Bach on the piano. And my uncle would come round and play jazz on the saxophone. And I’d go to school and we’d do Benjamin Britten’s The Little Sweep, and the next term we’d do My Fair Lady.

It was completely normal to juggle them all together.”When she was 15, her Aunt Eileen took her to London for the first time and introduced her to showbiz, operatic and otherwise “We went to a different show every night I saw Madam Butterfly – I’d never seen an opera before And a Tchaikovsky concert. I saw a musical called 1781, which was extraordinary, and I went to Abelard and Heloise, which changed my life completely.” Remembering how Diana Rigg (as Heloise) was loudly mocked for appearing sans clothing during the play, I wondered if this had been the inspiration behind Ms Garrett’s brief but notorious flash of naked bottom during a production of Die Fledermaus. “Something that amazed me when I whipped me kit off was that the reaction was exactly the same as with Diana Rigg 20 years before – that is, ridiculous, over the top. As if the papers had learnt nothing in that time.”The most interesting hiccup in Ms Garrett’s rise came in 1982, when her first marriage failed and her voice packed up completely.

She couldn’t sing, couldn’t hold a tune, could hardly produce a note – “maybe a tone, that was all I just couldn’t do it. I got a few jobs and bummed around, but I was really frightened I thought I’d blown it and lost it for good. There was apparently nothing wrong but I just couldn’t remember how to sing.” She went to her singing teacher to rebuild her whole range of notes (it took, she says, years) but also saw a shrink. “The idea was that I was probably riddled with guilt – that I’d left my husband to pursue my career – and had taken my voice away to punish myself. It all sounded a bit Californian, but it was interesting and I discovered a lot about my own resilience…”As she bustles about her large and airy house in the fashionable end of Highgate, where she lives with her second husband Peter and their children Chloe and Jeremy, it’s hard to imagine this strong, unsinkably optimistic woman being bothered by guilt.