The government’s marriage allowance allows taxpayers to transfer up to 10% of their unused personal allowance to their partner which can reduce their tax bill by up to £230 a year in 2017-18.

The government will now allow claims in cases where a partner has died before the claim was made and these claims will be able to be backdated by up to four years, effective from 29 November.

This measure is expected to have a negligible impact on the Exchequer.

The measure has been introduced to make the marriage allowance more widely available as HMRC figures have previously confirmed that take-up of the allowance has remained low.

Around a quarter of those eligible to receive the allowance have claimed the tax break.

Anne Fairpo, chairman of the Low Incomes Tax Reform Group, said: ‘This announcement corrects what has long been perceived as a harsh anomaly in the way marriage allowance claims are structured.

‘As the existence of the allowance is not widely known, it often happens that the first time a couple hears about it is after one of them has died and the question of a marriage allowance claim arises during the administration of their estate. But by then it is too late, because up to now the law has provided that a couple must be married or in a civil partnership at the time of the claim.

‘Today’s welcome change of heart by the Government will remove this obstacle, and the four-year backdating will enable couples who have been refused claims by the surviving spouse or civil partner to re-apply.’

 Report by Amy Austin