Liam, 22, moved into the houseshare at number 5 in September, three weeks into his first proper job — logistics coordinator, £24,500 a year, which he'd mentally converted to "about two grand a month" and budgeted accordingly.

Then the first payslip lands. £1,721.

He reads it at the kitchen counter with the concentration of a man defusing something. Income tax: £199. National Insurance: £80. And a line that says pension — £82, which he doesn't remember agreeing to.

"Auto-enrolment, mate," says Jordan, flatmate and self-appointed financial adviser, not looking up from his phone. "They opt you in automatically. You can opt out though — takes two minutes. That's £82 a month back. You're twenty-two. You'll be dead before you're old, and if you're not, future-you can sort it. That's basically a grand a year of actual nights out versus money in a box you can't open till you're sixty-something."

Liam looks at the payslip. £82 is his share of a Friday takeaway, a gig ticket, most of his phone bill. And retirement is — he does the maths — forty-five years away, which might as well be science fiction.