I have to disagree.
I earn about £25k and live on my own, I have a mortgage on a flat near the centre of Edinburgh (I could easily get a decent sized house further out), run two cars, spend money every few weeks driving to and from Hull (and eating out while there), and still put money into my savings.
If you can't get a mortgage on a property outside London with a combined income of £30k, you're doing it wrong.
Perhaps your opinion of a decent house is something much bigger than you need?
Two follow up points from either side of the argument:
- two people earning £15,000 each would be paying less tax than one person on £25,000 and so should be able to afford more.
- it very much depends on where in the UK you live and what house prices are in your area. There are some fairly expensive areas within London commuter distances where it may not be affordable to many people with a household income of £30,000 depending on what their circumstances are (i.e. do they have; student loans, credit card debt, children, etc.) and how much deposit they can save up.
As an example; a couple buying their first home as a £205,000 one bedroom flat (located an hour from a London Terminus) brought with an £11,000 deposit would cost circa £900 per month on a 3.75% mortgage, given that £15,000 would give you a take home salary of circa £1,100 that leaves you about £1,300 for the couple to live on. However that is assuming that banks would even lend you the £194,000 to start with, as an example, one only offering a loan of £99,000 for a couple on £15,000 each.
Current earnings vs mortgage payments also depend on how long the property has been owned for, as someone buying a 2 bed flat for sub £50,000 in the mid 90's would have cleared a sizable chunk of their debt with the property now worth circa £200,000 meaning that their loan to value ratio enables them to get a very good interest rate.
Even a couple having bought a two bedroom house for £200,000 6 years ago (for the same if not less than the one bedroom flat used as an example above) could have cleared circa £15,000 from their mortgage and with rising house prices they could well be on a fairly favorable interest rate which first time buyers could only wish to be able to offered on a property that they can only dream of being able to afford.