The Metropolitan Police force is to open its Special Operations control room for the Olympic Games later. The centre in Lambeth features the latest in security technology and closed circuit television.
A committee of MPs has said the problems with recruiting security staff for the Olympics should have been foreseen.
The boss of the government's Olympics' security contractor G4S has faced a dressing down from MPs for his firm's poor performance.
The head of G4S is under pressure to quit his £830,000-a-year job as he prepares to face questions from MPs