HM Revenue & Customs has defended a pilot scheme inviting people struggling to reach the organisation on the phone to tweet their tax queries.

Director of communications Stephen Hardwick said the measure, derided as “laughable” by some politicians, would be helpful as queries rose to a peak through January as the self assessment deadline approached.

Mr Hardwick said HMRC was working hard to improve its phone call responses after official statistics showed average call waiting times reached 10 minutes 21 seconds in September.

He compared the organisation with the Royal Mail by telling the BBC Radio 4 Today programme the number of call handlers was being ramped up for the seasonal peak.

Mr Hardwick said: “We are serious about the use of Twitter as a supplement to going online and using the telephone. What we don’t want people to do is to give us any personal details.

“It’s a very useful social media device to get guidance, to help point people to where they can get information online.

“It’s a pilot, it is starting small, but the whole point of social media is you answer a question once and hundreds or thousands of people can see the answer, rather than answering the phone to all of those people asking the same question.”

Mr Hardwick acknowledged HMRC “did not do well enough” answering the phone in September, with a third of callers failing to get through at all at the first attempt but he vowed the organisation was working to tackle the problems.

He said: “What we are doing for the self assessment peak in January, which is one of our two big peaks in the year along with the tax credits peak in July, is we are putting 1,500 people on the phones to help.

“We are a bit like the Royal Mail with the Christmas post - you don’t staff up all year for a very short-term peak, so we are moving people flexibly in and out of the telephones.”

Mr Hardwick said last July 89% of calls had been answered first time, and the same was targeted this month. He added: “There are around 10 million people who do the self assessment online. Half of them leave it until January and half of them leave it until the last minute.

“We have to, like any Government department, work within the budget we have and in a modern organisation like we are trying to be we are doing more digital online services for people, we are trying to provide people with the type of service they want, where they want it, when they want it.

“On the telephone we are not meeting the standards we want to provide and people expect and we are really sorry. We expect by the end of the month to have met people’s needs to get through on the phone but we would ask people to get on with their self-assessment early, don’t leave it until the last minute.”

After the Twitter proposal emerged yesterday, shadow Treasury minister Shabana Mahmood said it “beggars belief”, while Margaret Hodge, the Labour chairwoman of the Commons public accounts committee, said it was “laughable”.

Tory MP Mark Garnier said he was unable to think of even a simple tax query which could be expressed within Twitter’s 140 character limit.