As a general rule, a mortgage of 2.75 times your main income and 1 times your second is a prudent sustainable level, leaving you enough money to live your life.
Many people borrow far far more than this these days, but when interest rates rise, they are stuffed.
The temptation to borrow too much has fuelled house price inflation and left millions heavily in debt to the banks. Many have no choice but to be overleveraged now. They can blame the people who had no self restraint and who caused the huge bubble that has built over the past 25 years!
It's not been these people alone however, they had plenty of encouragement:
1) Successive governments for relaxing financial regulation in their clamour for increased tax revenues. They allowed lenders to become reckless. They also taxed the backside out of the already damaged private pension system, thus fuelling the buy-to-let market.
2) Banks for throwing far too much money at people and creating cheap introductory rates at the expense of standard variable rate customers! They created the mortgage tart - people who continually swithched from one cheap loan to another.
3) The financial institutions that provide personal pensions/endowments, for lying to savers. This brought about a loss in confidence in this sector. It was the poor value of these traditional pensions, their inflexibility and the fact that annuities don't form part of a policyholder's estate when they die. This exasurbated the closure of company final salary schemes. Thesed combined started the buy-to-let boom - people just wanting an alternative to protect themselves in retirement (and their offspring).
4) Estate agents and developers who inflate prices, especially new build.
The young have no chance of buying property at sensible prices. Our system is well and trully broken. The only people who can have things like this will be top earners and rich foreign investors. The rest will have to pay through the nose and rent.