Just because you got unlucky by being responsible doesn't mean everyone does or will.
I've known people in places where the property market collapsed and its ugly. And I know people think it can't happen in London, but 'it can't happen here' is about as myopic as it gets.
The property market collapsing (locally, not nationally) is only an issue when you want to sell. If you buy a house with an FHA mortgage (3.5% down), you will be underwater for many years no matter what. But it's a 30-year loan, why would you buy a house if you wanted to move in 3 years?
Plenty of people did this in the US (and I assume other countries) during the Great Housing Debacle of the early 2000's, it's called "flipping." The problem is when the music stops, and nobody wants to buy houses, you are stuck with it, and either need to default on the mortgage or suck it up and live there.
I've known people in places where the property market collapsed and its ugly. And I know people think it can't happen in London, but 'it can't happen here' is about as myopic as it gets.