London: Britain is to step up police patrols in areas with high Jewish populations, Prime Minister David Cameron said on Friday, while warning that it was impossible to provide "100 per cent protection".
The move came in the wake of last week's Islamist attacks in Paris, as well as a foiled plot in Belgium yesterday.
As security for police officers was also tightened, Cameron warned that all Britons should be "incredibly vigilant" in an interview with Channel 4 during a visit to Washington DC.
"These steps were taken because of what happened in Paris and because of the situation that we face generally," Cameron said.
But he also cautioned: "There's no way that you can give 100 per cent protection in a free and open society."
Jewish security charity the Community Security Trust welcomed the move, saying it had received an "unprecedented" number of calls from British Jews following the attacks in France.
"People are acutely aware that what happened in Paris could happen here," said the charity's director of communications, Mark Gardner.
"They need to be reassured that security and policing measures are in place."
Britain's terrorism threat level is currently set at severe, the second highest of five levels, mainly in response to threats from Al-Qaeda and Islamic State (IS) jihadists.
This means that a terrorist attack is thought to be highly likely.
Scotland Yard assistant commissioner Mark Rowley, meanwhile, also said that security for police was also set to be boosted.
He said the current number of people being arrested on suspicion of terrorism offences was unprecedented and rose 32 percent in 2014.
"This is not about officers being afraid to leave police stations or never going out on their own," Rowley added.
"It is about how do we assess the patrols officers are on, the incidents we send officers to, how we assess their day to day work".