Updates to this story
A problem importing data from an old computer system to a new one at Her Majesty's Revenue and Customs is causing errors in people's tax codes.
Ann Winterton, Conservative MP for Congleton said: "The advice is to ring to register that a tax code might be wrong, but the lines are constantly engaged, so people cannot get through. Will he look at that problem and sort it out?"
Stephen Timms, financial secretary at the Treasury - pictured left - admitted that there's a problem with tax codes.
He said: "It is the case that a new computer system is being used for PAYE (pay as you earn) this year. It is working very well and is enabling HMRC to hold in one place all the records on one person's employment and pensions, which was not possible in the past. As the hon. Lady has said, there has been an issue about tax codes, and HMRC will be working to iron out the problem well before the start of the new tax year. I will look into the issue about the phone line-for those who are interested, the number is 0845 3000 627."
In a separate written answer to a question, Timms gave information on how many employer PAYE returns are manually processed. In 2005-2006 the number was 3,798,120 but that dropped to 1,766,424 in the tax year 2008-2009.
He said that HMRC introduced a single national computer system to replace the previous 20 year old system. The National Insurance and PAYE service brings together all individuals' PAYE details onto one database.
*EyeSee Mr Timms is on Twitter. He was reflecting this morning on how to support the skills needs of the computer games industry and wants ideas. #digitalbritain