For example, the best deal for a £100,000 mortgage is probably Leeds and Holbecks's three-year discount of 2.25 per cent, which works out at a payable rate of 5.1 per cent. On a £100,000 mortgage, you would be paying £5,100 a year interest. The same mortgage from IF would cost £6,800 a year, after the initial six-month discounted period expires. You would need to borrow an awful lot on your current account and credit card to incur interest charges of £1,700 a year - the difference between the Leeds and Holbeck rate and the IF charge.