The government came under pressure this week to introduce a transferable tax allowance for married couples. In the Conservative manifesto and the coalition agreement there was a commitment to end the couple penalty and recognise marriage and civil partnerships in the tax system.  

Fiona Bruce, the Conservative MP for Congleton, tabled an amendment to the Finance Bill that would allow married couples to share each other's personal allowance. The principal beneficiaries of this change would be single-earner couples where the tax free allowance would be doubled. 

When asked about these plans David Cameron reiterated his support for introducing such an allowance. At Prime Minister's Questions a Labour MP pointed out that Nick Clegg, his deputy, had described such plans as patronising drivel prior to the election. The prime minister's comments were notable because barely 12 hours previously David Gauke, a Treasury minister had refused to back Mrs Bruce's amendment. 

The amendment to the Finance Bill was unconventionally not moved by Mrs Bruce but by fellow Conservative back-bencher Edward Leigh, although the Congleton MP later spoke and voted in favour of the motion. Speculation was rife that the government had wanted the amendment dropped, with several Labour MPs pressuring Mrs Bruce when she rose to speak to clarify why she did not initiate the debate. 

Starting the debate Mr Leigh noted that: "the present system is unfair and, specifically, militates against single-earner families." He went on to insist that we should "be concerned about families on fairly modest earnings who are desperately trying to look after their children, and who decide that someone, usually the mother, should stay at home and care for them". 

Based on the current tax thresholds a single-earner couple would save £1,495 if they were entitled to use both their and their spouse's tax free allowances. Mr Leigh went on to point out that the benefit would not only be financial: "While marriage accounts for 54 per cent of births, the failure of marriages - i.e. divorce - accounts for only 20 per cent of break-ups and 14 per cent of the costs of family breakdown, amongst all families with children under five." 

In her contribution to the debate Mrs Bruce suggested that: "As a government, we should send out a clear and credible signal to young people that we value marriage and encourage their aspirations in that respect, particularly as marriage acts as a stabiliser not just for the individuals within it but for the wider community."

From the Labour benches Kate Green MP criticised the plans, saying: "I have seen and heard no evidence, either this evening or during the many years that I have studied this subject, to show that a tax break persuades people to get married or to stay married … it seems extraordinary to spend public money on a mechanism that has no evidence to prove that it works effectively." 

Despite the commitments in the coalition agreement, when Treasury minister David Gauke rose to respond to the debate he said: "Although the government support the principle behind the new clause, now is not the appropriate time to bring forward such a measure." As the debate came to a close he added: "The government remain committed to exactly what we said in the coalition agreement."

Although the government appear committed to introducing a tax allowance for married couples they are eager to do it at a time of their choosing - which appears not to be now. The Evangelical Alliance and other Christian and family campaign groups will maintain the pressure on the government to ensure that they fulfil this promise.