Tax forms are too complicated and must be made simpler, a government committee has said.

The Committee of Public Accounts has published a report which finds HM Revenue and Customs has not done enough to make filling in a tax return a simple task, and money is being lost in unpaid tax.

Edward Leigh MP, chairman of the committee, said: “Completing a tax form should be made much simpler.

“Too many people are unintentionally making mistakes, resulting in an estimated underpayment of tax each year of some £330 million.

“It is puzzling to say the least that no similar estimate has been attempted of the amount overpaid to the taxman as a result of such mistakes.”

Mr Leigh called on the HMRC to make an estimate of the amount overpaid and also publicise common errors leading to underpayments and overpayments.

The report also criticised the department’s website for being like a “maze” and for sending frustrated callers around the system.

People with a less than average reading age will also have trouble understanding the leaflets, the report added.

HMRC spends £35 million a year on producing and distributing printed forms and other guidance.

It also spends £55 million a year answering 12.5 million enquiries on how to complete forms through 13 telephone helplines, face to face meetings at 279 enquiry centres or via its website.

Although 95 per cent of telephone enquiries get the right guidance, taxpayers sometimes receive inaccurate or incomplete advice because more complicated enquiries are not always referred to expert staff, the report found.