How should tax evasion be punished?

The Chartered Institute of Taxation policy director Patrick Stevens says:

"HMRC's overriding objective is to bring in as much as money as possible for as least cost as possible, so that net-net, the Exchequer is better off and we've got more money to pay for schools and hospitals..."

But former director of public prosecutions Sir Keir Starmer disagrees: "In my view criminal prosecution should be the default position for tax evasion..not civil penalties."