For a lot of Tories, Boris Johnson is effectively the Conservative party leader-in-waiting.
But Boris is a keen student of political history and he looks back at other leaders-in-waiting, like Michael Heseltine for example, who did not seize the crown.
His speech today was quite carefully calibrated: He was funny; He made them laugh; He teased the Prime Minister; He was quite optimistic and buoyant amid all this economic gloom.
But he didn't stray away from his subject - he concentrated on London and he made sure it could not be seen as a direct leadership pitch.
I think it is in his interests to continue like that because if he does the party will be tempted to deploy him quite heavily in the next election.