HM Revenue & Customs has been criticised by a Public Accounts Committee for failing to implement an 'effective and efficient debt management system' that could recover £17.5bn in overdue tax bills. HMRC's inability to automatically link debts owed on different taxes by the same taxpayer came under fire for creating 'barriers' to the department's efficiency. In 2007-08, the department collected around £450bn in tax and national insurance contributions from 35m taxpayers. At 31 March 2008 the £17.3bn in tax was still outstanding, with interest and penalties amounting to £4.5bn. Committee chairman Edward Leigh MP said that although HMRC had started to collect tax through the use of credit cards and debit cards it 'has been slow to take advantage of the key techniques used by other organizations to manage debt owed to them'. HMRC has said that it cannot afford to develop an IT system linking taxpayer's records, which will cost more than £250m to build. But Leigh has noted that it is a 'crucial' measure 'to effective debt management and HMRC should introduce a staged programme towards that end'. In 2007-08 tax debts increased by 22% which the committee speculates could be a growing problem for HMRC 'while making allowances for people and businesses in temporary financial difficulties.'