We asked HMRC why response times were very poor at the end of 2020–21. HMRC said in the first half of 2020–21 it had diverted 5,000 customer service staff to work on COVID-19 support schemes. HMRC also said that during this period it did not have backlogs. It told us that in the second half of 2020–21, its customer services team had to continue to support the COVID-19 support schemes and 3,000 additional customer service staff were diverted to work related to the UK leaving the EU. It also told us that it “stayed strong on the fundamentals of the tax system”, and it successfully managed the annual peaks in self-assessment and tax credits. It said that because of the priorities of paying money to vulnerable people, COVID-19 and customs, given the UK’s exit from the EU, it had to put other parts of tax activity to one side, and it started to build-up a “bit of a backlog”.47