The assistant commissioner of the Metropolitan Police also said the police needed help from communities to tackle terror because of the thousands of people who are subjects of interest to the security services.
He said: “Our ability to keep our radar on them, that’s no longer just just a job for police and security services.
“We will always do what we can do to improve our business but it is going to take a whole community effect.”
Meanwhile, Lord Evans also sounded a stark warning about the potential for Russian interference in the UK’s democratic process.
He said: “It would be extremely surprising if the Russians were interested in interfering in America and in France and in various other European countries but were not interested in interfering with the UK because traditionally I think we have been seen as quite hawkish.
“I would be surprised if there had not been attempts to interfere with the election, equally I don’t have insight into exactly what was going on behind the curtain during the election period.
“But I would be very surprised if there was not some form of conflict going on.”