From April 2015, people will be permitted to transfer £1,000 of their personal tax allowance to their spouse or civil partner – an increase on the £750 allowance promised in the Tory manifesto.

The Prime Minister – announcing the scheme ahead of the start of the annual Conservative Party conference in Manchester on Sunday – said it said will be worth up to £200 a year for married couples, including 15,000 in civil partnerships.

They will receive the benefit at the end of the tax year in 2016.

The new allowance, which is not available to couples which include a higher rate taxpayer, is aimed at couples where one partner has not used all of their personal allowance or does not work at all.

Labour said the move would benefit few couples.

Shadow chief secretary to the Treasury, Rachel Reeves, said the marriage tax break would not even help two-thirds of married couples and said Cameron was out of touch if he “thinks people will get married for £3.85 a week”.

She added: “And even for the minority who might benefit, it will be far outweighed by what David Cameron’s Government has already taken away in higher VAT and cuts to child benefit and tax credits. In most cases, the extra payment will be paid to men, even though it is women who have disproportionately lost out so far.”