The Home Secretary has described the terrorism threat facing the UK as "severe" and "growing".
And the police are cracking down on suspicious individuals.
Meanwhile out on the roads this weekend
Four people have been killed and three others injured in a road crash in the Lake District, police said. The driver and two passengers of a Ford Fiesta and the driver of a Vauxhall Astra died in the collision.
In Manchester Cyclist is killed in hit-and-run; in Devon a pedestrian was killed by a hit and run driver
A six-year-old girl has died after being knocked down by a car as she crossed a road in West Yorkshire.
A 19-year-old woman and a 23-year-old youth have been killed when the car they were travelling in hit a railway bridge in the West Midlands.
Two men have been arrested on suspicion of dangerous driving after a crash that killed a man and left five others hurt.