MPS demand that HM Revenue & Customs provides alternatives to its notorious 0845 numbers in a highly-critical report published today on the department's dealings with members of the public and tax professionals.

The Treasury Select Committee criticises what members described as "unacceptable difficulties" contacting HMRC by phone during peak periods.

It highlights "endemic delays" in responding to postal inquiries.

The report also deplores an increasing focus on online communications which its authors say could exclude those without good internet access.

The report says: "There is considerable dissatisfaction among the public and tax professionals with the service that HMRC provides to taxpayers and benefit claimants. There is a serious risk that if communicating with HMRC becomes too time-consuming, difficult and expensive, respect for the tax system, and with it voluntary compliance, may be undermined."

A key recommendation is improving service from HMRC call centres, particularly for complex queries.

MPs criticise the expense of calling HMRC's various 0845 telephone lines, particularly from mobile phones.

The report adds: "At a time when calls are not being answered quickly, it cannot be acceptable that those without landline telephones – often less well off members of society – may be being charged more as a result of the use of 0845 numbers.

"We recommend that HMRC investigate alternatives to 0845 numbers, including 0345 and freephone numbers."

As an interim step MPs ask HMRC to look at providing tax credit claimants with alternative numbers.