As a general rule, mortgage companies will allow you to borrow three times your salary, or two and a half times your joint salaries if you're buying with someone else.
However, in the current market there are many different types of mortgage available, some of which will let you borrow more than this. For example, some companies will allow two people buying together to borrow three times the greater salary and one times the lesser.
There are also many innovative schemes around, such as those that allow borrowers to add the rental income from letting one room to their salary before their income multiples are assessed.
It's worth seeking advice from two or three independent mortgage or financial advisers to find the best deal for you. Remember, though, that even if interest rates are low now, there's absolutely no guarantee they'll stay that way.
Never keep back any information on debts or county court judgments when securing a mortgage; it could come back to haunt you.