I'd be curious to know too but it's not my subject, I'd get the experts in.
First thing would be to reverse the cuts made to HMRC and expand operations.
Just one of many sites here:
https://taxjustice.uk/
"For more than a decade HMRC has faced year on year cuts to funding at the same time as ongoing internal re-organisations. Together these have led to a situation where HMRC has been variously described as a government department in “crisis” and “not fit for purpose”.
This could apply to almost everything the tories have done since 1979.
With HMRC they've been killing the goose which lays golden eggs! Instead they left a huge t*rd in the nest, called Brexit.