Income Tax Act 2007 section 53

Transfer of unused relief: general

Section 53 sets out the general rules for calculating whether a married person or civil partner has unused married couple's allowance that can be transferred to their spouse or civil partner, including how to work out the "comparable tax liability" and the procedural requirements for making a transfer election.

• The comparable tax liability is the individual's income tax calculated through the standard steps but ignoring any double taxation relief — this ensures double taxation relief is always given last in the ordering of reliefs.
• Where gift aid donations have caused the married couple's allowance tax reduction to be restricted, the comparable tax liability must be reduced by the amount of that restriction, limiting what can be transferred.
• A notice to transfer unused relief must be submitted within four years of the end of the relevant tax year, in the form specified by HMRC, and once submitted it cannot be withdrawn.
• A person who is entitled to a credit against income tax under a double taxation agreement is treated as having a tax reduction for the purposes of this calculation.