The amount you can borrow as a mortgage is determined by how much deposit you can put down, and how much you can afford as regular repayments.
Factors to bear in mind
The amount that you want to borrow is expressed as a ‘multiplier’ of your income. So, if your income is £18,000 per year, and you want to borrow £54,000, the income multiplier is said to be 3 times.
Length of expected occupancy
The Financial Services Authority produces tables comparing different products from various providers, on their website.