s 40 Election for transfer of allowance under section 39
(1) An election under section 39— (a) must be made not more than 4 years after the end of the tax year to which it relates, and (b) cannot be withdrawn. (2) If an individual makes an election for a tax year under section 39 the individual is treated as also giving notice under section 51(4) that section 51(1) (tax reductions for married couples and civil partners: transfer of unused relief) is to apply for the tax year.