New data from HMRC shows that efforts to improve customer service levels on its telephone helplines are proving only partially successful, with a dip in performance in the first three months of this financial year.
The statistics, released in HMRC's Business Plan Indicators Q1 2013-14, are published the day that HMRC director general personal tax, Ruth Owen, is due to face the Public Accounts Committee to give evidence on charges for customer calls.
They show that overall, agents in HMRC call centres handled 83% of call attempts in April 2013, but this percentage dropped to 80.8% in May and fell further to 70.2% in June.
Rates were similar in the same three months of last year, and reached a low of 49% in July 2012.
However, since then they have picked up to over 90% in the last three months of the year, eventually reaching 95% in February 2013.
In the most recent quarter, average wait times for callers in a queue doubled over the period, up from just over three minutes in April 2013 to nearly six and a half minutes in June, when the number of callers giving up on their call climbed above 800,000.
Average waiting times in the previous quarter were lower, reducing to a little over one minute in February 2013.
There was a similar decline in HMRC's performance in answering calls that did get through in the latest figures, with only a third (36%) being answered in under two minutes in June 2013, compared to 69% in April. June also saw a steep rise in callers who waited between 10 and 20 minutes to be put through, which accounted for 37% of all calls, compared to 9% in April 2013. This was also down on HMRC's performance for June 2012 which saw similar call volumes, but only a quarter (25%) of callers waited between 10 and 20 minutes to be answered.
Compared with the same period last year, HMRC's latest figures show that overall abandonment volumes have come down substantially, from highs of over one million calls.
Results from the contact centre customer experience survey were mixed - while 80% of callers to the child benefit helpline were happy with the ease of getting in touch, only 56% using the business tax line felt the same.
