Did Channel 4 also ask whether they still beat their wives? That used to be standard questioning where the subject was damned if he said yes and damned if he said no.
Reply "Yes I have/had offshore interests" - result, damned for saying yes.
Reply "No, I do not have/have not had offshore interests" - result, damned for telling lies. ("Well, they would say that, wouldn't they?" Mandy Rice-Davies)
Reply "Mind your own business" - result, damned for "refusing to admit it"
No reply at all - result, damned for not giving channel 4 a chance to damn them for any of the other replies.