Olympic security staff must ensure venues are safe and prevent demonstrators from bringing equipment like banners and tents into the stadiums and arenas.
At the same time they must ensure that their work does not create long queues leaving spectators unable to see the events they have tickets for.
All of this will be achieved says G4S, the company that is in charge of the recruitment drive.
But some staff who have worked on the operation have told ITV News they have witnessed security breaches by G4S staff already working at Olympic venues.
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Cloud continues rolling in from the west overnight which, combined with fresher winds will keep temperatures above freezing here.