The New York Times has an article on Gabriel Zucman's estimates of the sums hidden in tax havens this morning. I recommend reading it although I think he seriously under0estimates the sums involved which i hope the Tax Justice Network will address (again).
What attracted me was the closing paragraph which said this:
What’s beyond question is that there is no economic, political or moral justification for tax evasion — it exists only because of the political influence that wealth buys. A society that fails to fight widespread tax evasion proclaims its own corruption.
That's what HMRC is permitting in the UK, proclaiming its own corruption at the same time as it cooperates with the cuts the government is imposing upon it which undermine its ability to tackle this cancer within our society. It's time we woke up and realised the threat.