Calls to HMRC cost public £136m last year

• Value of customer time whilst they waited for an answer added up to £103m

• HMRC admit to not delivering the standard of service to which they are committed

• Plans to spend over £30m on improving performance levels

According to a report from the National Audit Office (NAO), the delays costs customers £33 million in call charges, with the estimated value of customer time whilst they waited for an answer was £103 million.

The report said that as many as 20 million calls to HMRC hotlines - many of which are premium 0845 numbers - were not picked up at all in 2011. People who did manage to get through waited an average of 282 seconds for a response from an adviser, a jump from 107 seconds in 2009/10.

Around 6.5 million people were left on hold for periods of ten minutes or longer in the first part of this year.

The report stated: “Depending on the tariff they pay their phone company, customers are charged once their call is connected even if they are held in a queue,” the report said.

“We estimate that if HMRC improved performance to answer 90% of calls and reduced waiting times, it could save customers around £52m a year.

“HMRC currently plans to spend £34m to achieve this level of performance.”

The NAO report also found that there had been some progress made since HMRC’s huge recruitment drive, with the thousands more staff brought in meaning the 74 per cent pick-up rate was significantly higher than the previous year’s total of 48 per cent.

However, there were warnings that the figures likely underestimated the issue, as calls are counted as answered even if they are not picked up by an adviser.

Margaret Hodge, chair of the Public Accounts Committee said: “When people have no choice but to contact the Revenue to discuss their tax affairs, I find it totally unacceptable that HMRC uses costly 0845 numbers and charges people for the privilege of waiting for the department to pick up.”

Chief executive of the Taxpayers Alliance Matthew Sinclair added: “This report exposes a shameful level of service at HMRC.

“Taxpayers will be outraged that HMRC could let 20 million phone calls go unanswered and yet still claim that it is outperforming some arbitrary target.”

A spokesman for HMRC said: “In 2010/11 we answered 48 per cent of all call attempts, rising to 74 per cent in 2011/12.

“By late 2012 we were answering over 90 per cent of calls to our contact centres. We are well aware that in the past we have not delivered the standard of service to which we are committed.

“We are determined to build on this progress and we have invested £34m so we can deliver on our improvement targets earlier than planned.”