The Metropolitan Police officer also advised people to run away in case of a terror attack.
The biggest terror threat to Britain emanates from "home-based terrorists", UK's senior-most counter-terrorism police chief said today and advised people to run away as fast as possible if they get caught up in a terrorist attack.
Scotland Yard assistant commissioner Mark Rowley said that the country faces the most serious terror threat from "home-based terrorists" in the UK.
"Most of them aren't people who have travelled to Syria, but they are being inspired, trying to pick up weapons, to plan an attack here. That's what we've been wrestling with most of all. We've had a steady flow of people thinking about that sort of attack," Rowley said.
He confirmed that Britain's largest police force had hundreds of investigations ongoing, ranging from extremists right on the periphery through to small numbers of the highest risk operations.
The Metropolitan Police officer also advised people to run away in case of a terror attack.
"So let's be really clear - run as far away as possible and when you can't run any further, hide, and then tell - call the police because we've got the people, the resources, the firearms to deal with it. It's very straightforward," Rowley told 'Evening Standard' newspaper. "It may seem blindingly obvious, but some people don't run, they will duck down where they are, do all sorts of different things in the panic," he said.
Rowley was emphasising official advice from the UK's National Counter Terrorism Security Office, which stresses that people under attack should run or hide, rather than submit to their assailants' demands.
If it is not possible to run, Britain's counter-terrorism police stress that it is important to find cover from gunfire behind substantial brickwork or heavy reinforced walls.
"We should all do everything possible to stop attacks happening, but when we look at the events of the past few months in Europe it would be foolish if we were not to put out advice saying if you get caught in something here are some simple rules about what to do and give yourself a better chance of survival," Rowley, the UK's national head of counter-terrorism, told the newspaper.
"This is based on what's happened in attacks across the world. If you get a chance, run to get away, hide and call us," he added.
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