pay back

"As a car insurer, for every £1 of premiums you take in, you pay back almost £1.05 in claims," he says.

Instead, when the mortgage is refinanced or the house is sold, the borrower pays back the original loan, plus 20% of its increase in value.

The idea is that borrowers are more likely to pay back — and less likely to default on — a loan attached to the home they actually live in.

"I think of it as paying back a little bit. I was helped out quite a lot," he added.

Governments borrow money from investors by selling bonds - which is a loan the government promises to pay back at the end of an agreed time.