Sir Mick's 36-year-old daughter has, however, still to work out a coherent pro-drugs philosophy.

When Mandrake inquired why, she could only say that "the old system had always seemed to work and, um, it was easy to remember because it was C for cannabis".

She was speaking at the launch of her Belvedere Jagger Dagger, a diamond and sapphire-encrusted ice pick she designed for the vodka company.

This, too, took some explaining. Some people wondered if its design had been inspired by the old Nazi insignia, a suggestion she was quick to deny.