Average HMRC call waiting times have tripled over the last 18 months, resulting in a loss to taxpayers of £97 million last year, according to a report by The National Audit Office (NAO).

Research indicates that the quality of service may have been affected by the HMRC staff reductions that took place in 2014/15.

Calls handled fell to 71%, falling short from HMRC’s target of 80% over the first 10 weeks. Performance declined further over the first 7 months of 2015/16 with average waiting times tripling compared to 2014/15.

Call times peaked at 47 minutes for self-assessment tax returns during the deadline week for paper returns in October 2015.

Taxpayers are, however, mostly satisfied with HMRC services with only 1 in 5 disagreeing.

An NOA survey found that 58% of taxpayers rate its services positively, 21% rate them as average while 21% rate them as terrible.

Customer satisfaction was highest among taxpayers contacting HMRC online, compared to those contacting by phone.

HMRC are introducing digital tax accounts, with taxpayers providing information and make payments anytime during the tax year. It is hoped that the changes will increase efficiency, reduce administrative burden and improve overall levels of tax compliance.

Amyas Morse, head of the NAO, said:

“HMRC needs to move forward carefully and get their strategy back on track while maintaining, and hopefully improving, service standards.”