HMRC takes on evening staff to improve performance
Tax staff are being taken on to work in the evening and more online services introduced in a bid to improve performance at the UK's tax authority.
Lin Homer, chief executive of HM Revenue and Customs (HMRC), apologised again to a committee of MPs for the authority's call-handling figures.
HMRC's record of answering calls was accused of being "staggeringly bad" by one MP.
Only half of calls were answered successfully between April and June.
Ms Homer, appearing in front of the Commons Treasury Committee, said HMRC struggled to cope during those months but managers had introduced a series of changes.
This, she said, had led to an improvement between July and September when 76% of enquiries by phone were dealt with either by a member of staff or an appropriate recorded message.
She said that performance during the second three month period was "marginally higher than last year".
But Conservative MP Mark Garnier said this was "completely unacceptable" with 24% of calls still not being answered.
He said that if HMRC was a commercial service it would have gone bust with that performance.
Ms Homer said that a new telephony system had been introduced which allowed calls to be dropped into any call centre, so that up to 20,000 staff could be deployed to answer the phone at any one time.
She also said there was no evidence that taxpayers "tossed their tax return over their shoulder" if they failed to get through to HMRC on the phone.
A week ago, the tax authority was criticised for its call-handling performance by another committee of MPs - the Public Accounts Committee - which accused HMRC of failing UK taxpayers.