HMRC's tax investigations reclaimed just under £13.14 billion in 2018/19, according to its annual report and accounts.
The Revenue's actual compliance yield stood at £13.138bn last year, an increase of £2.7bn on the previous year's figure of £10.3bn.
Overall, HMRC fetched a record total of £627.9bn in taxes and duties on behalf of the Treasury in 2018/19 - up 3.6% year-on-year.
The Revenue claimed last year's total tax yield could have been higher if it did not have to divert around 5,400 full-time employees to prepare for Brexit.
Jon Thompson, chief executive at HMRC, said:
"There's no denying this [Brexit preparations] has had an impact on our wider plans.
"We've had to delay for now on some of our other projects, such as further improvements to our digital services.
"We've had to balance our work alongside the huge, complex task of preparing our customers for the UK leaving the EU, with or without a deal."
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