By Jennifer Hill

LONDON (Reuters) - Fees on fixed-rate mortgages have almost doubled in the past year, as lenders vie to increase margins amid the credit crunch, data shows.

Application fees on the five most competitive three-year fixes have risen 96 percent to 1,132 pounds from 578 pounds a year ago, according to online mortgage company mform.co.uk.

Typical arrangement fees on best-buy two-year fixes have increased 48 percent to 1,478 pounds from 999 pounds over the same period.

The rising cost of arranging a new mortgage is the latest hurdle faced by borrowers, 1.4 million of whom are coming to the end of existing fixed rate deals this year, according to the Financial Services Authority.

Lenders have been pulling cheap fixed rates, cutting the maximum loan-to-value and tightening their lender criteria as problems in global money markets continue.

Despite three quarter-point cuts in the Bank of England base rate since last October -- to 5 percent from 5.75 percent -- there has been little reduction in rates on the top mortgage products.

The average interest rate on the top five two-year fixed rate mortgages is 5.59 percent, compared with 5.67 percent six months ago. Typical rates on the cheapest three-year fixes are 5.66 percent, down marginally on 5.83 percent.

Francis Ghiloni, marketing and business development director at mform.co.uk, urged borrowers to focus on the true cost of home loans, taking into account associated fees and charges.