Surprise tax bills for 1.6m

The tax office, Revenue and Customs, is writing to 1.6 million taxpayers to tell them that they underpaid hundreds of pounds in tax last year.

The average shortfall of £537 will be taken out of pay packets over the financial year starting next April.

Underpayments happen every year, because the tax system isn't able to reflect job changes at once. And inaccuracies can arise if the taxpayer has more than one job or pension.

Even more people will gain from the recalculations. From next week HMRC will start paying refunds to 3.5 million taxpayers, with an average credit of £379.

Where paying a unexpected tax bill will cause hardship, tax officials have promised that they will allow those affected to spread the payments over a longer period.