I am about to make a guess.
There are, however, many signs that the sums involved are substantial and that they are growing. In the year to March 1975 the amount of evaded tax in major cases which the Inland Revenue was able to uncover amounted to some £17 million. As a proportion of the total tax yield this was only about one-fifth as much as the Revenue secured 15 years earlier. I am afraid, and I believe most hon. Members will agree, that there is little reason to suppose that the standard of compliance is now much higher than it was. Right hon. and hon. Members on the Tory Benches always talk about a great erosion of tax morality over recent years. The fact is that the amount of tax evasion uncovered by the Revenue has fallen by 80 per cent. in recent years, although according to the Conservative Party, the degree of tax morality is now much lower than it was.