I've done some further reading since then and it sort of a bit like that but sort of not. In a British interest only mortgage,
at the end of the term you have to pay up the capital. Which is why if house prices go down, people with they mortgages are stuffed. It seems like in Sweden, you don't have to pay any capital once the capital owed is less than 70% of the value of the property - so people just delay it forever and pay up at such a piddling rate that it would take the average punter 140 years to pay off. So, like the vanguard of modernity they are, they bequeath their kids debt rather than an asset. Now the legal beaks are forcing them to get the job done in a mere 105 years. Mental. The Japanese do this as well incidentally (ie 100 year mortgages).
I was also surprised to learn that our esteemed egalitarian Swedes are amongst the most indebted citizenries around - coming in at number 6 on the oecd list of household debt. Norway are number 3 and Denmark number 1.
https://data.oecd.org/hha/household-debt.htm
Perhaps we have a reason for these countries topping happiness indices of which I was previously unaware - they live high on the hog on the never never !