“I don’t like spiral staircases,” says Chris Lowe. “And that’s the first time that’s come out in an interview.”

Call it an exclusive. You heard it here first. The Pulitzer is in the post.

The revelation comes as we discuss the origins of the Pet Shop Boys, one of the UK’s most important and influential bands.

This year marks the 40th anniversary of their debut single, West End Girls – a claustrophobic trawl through London’s nightlife that launched a four-decade voyage into smart, irresistible pop.

But before they were Pet Shop Boys, the duo had other lives. And that’s where we join them, reminiscing about the days before they bumped into each other at a Chelsea electronics shop and a musical partnership was born.

Neil Tennant, erudite front man and lyricist-in-chief, grew up in Newcastle, attending the strict, all-boys St Cuthbert’s Catholic School that later inspired songs like It’s A Sin.

Aged 18, he left to study history in London before taking a job at an insurance office. It was the height of the glam rock era, and he embraced the adrogynous look of his musical hero, David Bowie.

“I used to walk down the Kings Road in a white tank top and women’s shoes with big platform heels,” he recalls. “Gay men used to make comments as I walked down the road.”

“That’s how you dressed for work in the insurance brokers?” asks his bandmate, apparently hearing the story for the first time.

“The guy I worked for was very gay,” Tennant explains. “He’d lived through the ‘60s and he used to take me out for lunch and tell stories about The Rolling Stones.

“I think he might have had a thing for me, but I didn’t realise it at the time.”

Lowe, meanwhile, was in Liverpool training as an architect, incubating his dislike of twisty stairs (the geometry is fiendishly difficult, apparently).