MPs will have their mileage allowances slashed from April next year despite more than 100 members voting to keep the current allowance.

At present, MPs claim 57.7p for the first 20,000 miles they drive and 26.6p thereafter. This can add up to more than £16,000 a year for drivers completing 30,0000 miles.

But the Commons rejected a motion to keep the original rate, which will now be cut to 40p a mile for the first 10,000 miles and 25p thereafter.

Despite the new allowances being introduced under Inland Revenue guidelines, one MP claimed the new system was ‘grotesquely unfair’ and failed to take into account constituency sizes.