I don't think that had been invented when I was young, Bonzo!

Don - there is tax evasion (and this is not it) and there is tax avoidance. Tax avoidance occupies a continuum from actually claiming the allowances to which you ARE entitled and to which you are intended to be entitled, to creating very artificial structures and transaction sequences to try to get round parliamentary intention. What Ken was up to is at the less dodgy end of the spectrum. Not nice, but not that nasty. What Boris did was get his mates to change tax law for his betterment. Verging on corruption.