The next Tory Prime Minister: Bruce Anderson says that David Cameron is one of the most important politicians of the early 21st century, and is heading for No. 10.

On Monday morning, a tense young politician was rehearsing a speech. The performance was less than fluent; the delivery was far too fast. The youngster's peace of mind did not benefit from his growing awareness that he was being overheard. A number of journalists had managed to slip into the hall.

Twenty-eight hours later, the rehearsal turned into the live performance. David Cameron had decided to speak without notes or an autocue. The previous day, Malcolm Rifkind did the same, but Sir Malcolm has been one of the two or three best speakers in Britain for the past 20 years, since he was David Cameron's age. When Mr Cameron dispensed with the normal speech-maker's aids, which Margaret Thatcher always used, he was gambling his leadership campaign on his success.

Fifteen minutes later, the gamble had succeeded. Judged solely by content, it was not a great speech. No one reading it would appreciate its significance. But the effects outweighed the words. This speech was far more than the sum of its parts. It …