Comments from me were included in a report on HMRC's failure to collect customs duties owing at UK ports on Radio 4 on Wednesday night. The losses are initially estimated at £2 billion: they could be a great deal higher because that loss only relates to garments and shoes.
The report is here. Start at about 22.45.
And note first of all that HMRC would not comment. And second note that they still have the gall to claim that they have the tax gap under control.