Last week HMRC chief executive Jon Thompson wrote to the select committee outlining a restructuring of the top levels of HMRC organisation, with the four existing lines of business to be merged into three new groups, starting in October and finishing by December.

Thompson wrote: ‘These changes will help us to become an organisation that is truly focused on customers, providing great customer service and designing policies, products and processes with customers in mind. They will also enable us to deepen our specialist skills and knowledge, by bringing together teams engaged in similar work allowing us to respond more flexibly and speedily to changing business and customer needs.’

However, Tyrie replied immediately, saying that while ‘there may well be a good reason for it’, the committee was concerned about the number of times HMRC was changing its structure.

‘There appear to have been over a dozen major reorganisations in HMRC since the merger in 2005. There is a trade-off between stability and what may work better on a management consultant's whiteboard,’ Tyrie wrote.

In his first appearance before the select committee, shortly after taking up his new appointment, Thompson told MPs he was aware that HMRC staff engagement surveys consistently revealed lower levels of satisfaction than in other departments.

Tyrie’s letter states: ‘Lack of stability may have contributed to low staff morale in HMRC, at least since 2009. You told us on 8 June that staff morale had improved. But it remains well below the Civil Service average.

‘I would be grateful for your assessment of the impact of these reorganisations on morale, and of whether those that require office closures have a larger impact on morale than those that do not. I would also be grateful for your assessment of the effects of relatively low morale on the capacity of HMRC to protect the yield.’

The latest high-level reorganisation sees HMRC introduce a new customer strategy and tax design group, an expanded customer services group, and a combined customer compliance group. This follows a major announcement in November 2015 that HMRC would close its existing 137 offices, replacing them with 13 regional hubs of which the first, in Croydon, will be opening in the coming months.

Tyrie said: ‘On Tuesday, I pointed out that HMRC had been reorganised to some degree nearly once a year on average. The last one was in November 2015. On Wednesday, they announced another one.

‘Perhaps all this turbulence is necessary. Perhaps any benefit will be offset by lower staff morale. Time will tell.’

Jon Thompson’s letter to Andrew Tyrie is here.

Tyrie’s response is here.