Blair would have been wiser to rely on blind trust than to have issued that dossier

No popular impression is more precious to those who govern than the impression on the part of the governed that more is known than can be divulged.

William Whitelaw understood this better than most. When I was a callow young Tory MP in the 1980s, and he was home secretary, I was briefly caught up in a flutter of backbench concern about telephone-tapping. More of this, it seemed, was going on than had been supposed, and the means of democratic oversight did not seem to exist. A small group of us on the government benches, all backbenchers, asked if we could talk to Willie about the problem. Alongside my friends, and not without trepidation, I entered the great man’s Commons office.

The home secretary roared his welcome and, spurning his big desk, gestured us into comfortable armchairs. Out came a whisky bottle and tumblers, and what seemed like half pints of the stuff were dispatched; there was no saying no.