Sir Geoffery Clifton-Brown, chair of the committee, said: ‘Given that citizens have no choice but to engage with HMRC, it has a responsibility to aspire to the highest standards of service. Unfortunately, what we have instead is a tax authority excavating its way to new lows in service levels every year.

‘Worse, it seems to be degrading its own services as a matter of policy. HMRC is an organisation in defensive mode and needs bold and ambitious leadership to begin to chart its recovery.’

The latest PAC report into HMRC service levels is highly critical of HMRC, saying that the tax authority appears to be intentionally running down phone services to force people onto online services.