Question to the HM Treasury:

To ask the Chancellor of the Exchequer, how much the marriage tax allowance has cost the public purse; how many married couples have been eligible for it; and how many and what proportion of eligible married couples have benefitted from it in each year since it was introduced.

This question was answered on 27th March 2019

HMRC publishes the estimated cost of tax reliefs annually and the latest estimate can be found here:

https://www.gov.uk/government/statistics/main-tax-expenditures-and-structural-reliefs

HMRC’s projection of the cost of the Marriage Allowance include the anticipated full take up of the allowance after all retrospective claims have been made, as the allowance can be claimed retrospectively for up to four years:

£ million	2015-16	2016-17	2017-18
Marriage Allowance	680	735	835

. Around 4.2 million couples are estimated to be eligible to claim the marriage allowance. The table below shows the approximate proportion of those who are eligible and are estimated to have made a claim for marriage allowance.

%	2015-16	2016-17	2017-18
Marriage Allowance	16	44	67