If you are married or in a civil partnership, you could potentially claim money back from HMRC for this reason alone. The government provides tax breaks for couples when one partner does not pay tax (i.e. earns less than £11,500 personal allowance level) and the other pays a basic tax rate of 20%. You can even claim if your partner has died since April 2015.
The tax break varies year on year; for the 2017 tax year, it stands at £230 and you can claim for previous years since the scheme was introduced in 2015 up to £432, totalling £662.
Over 3 million couples are potentially missing out on this, according to media reports. And why was the allowance introduced in the first place? Because “the Government values commitment by recognising marriage and civil partnerships in the tax system”.