Yes you can, but it's a bit more complicated. This is because you have to transfer £1,250 to take advantage – nothing more, nothing less. This means if you've less than £1,250 left of your allowance, you could exceed your personal allowance. If that happens, you'd end up paying tax on the amount you've gone over. There will still be a net gain for the two of you, just not that much.

This is how it works:

Part-time Peter decides to put in a few extra shifts at the chippy and his earnings go up to £11,700 a year. His full personal allowance for the year is £12,500, so by transferring £1,250 to his wife, he's left with a personal allowance for the year of £11,250.

Full-time Fiona still gets the full personal allowance increase of £1,250 to £13,750 when Peter chooses to make his transfer.

However, Peter now earns £450 more than his personal allowance, meaning he'll pay basic-rate tax for the year of £90. Meanwhile, Fiona gets an increase in her personal allowance of £1,250, so she'll get to keep an extra £250 (the 20% tax she would have had to pay).

The net benefit to Peter and Fiona is £160 – still worth having.

This year, the basic personal allowance for most is £12,500, meaning that's how much you can earn in the tax year before paying tax. So only if the lower earner in the couple earns less than £11,250 (£12,500 less £1,250) will they get the full £250 basic-rate tax saving.