Security services have foiled 13 terror attacks in the UK over the past four years, according to the country's most senior counter-terrorism expert.
Assistant Commissioner Mark Rowley, of the Metropolitan Police, also said they were working on 500 live investigations at any given time in order to reduce the threat
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Rowley said: "The public are making a great contribution, which is critical to us all working together to protect ourselves from terrorism.
"Some of that information is a change in someone's behaviour, some of that's about suspicious activity. Sometimes that public information has actually started an investigation. Other times it's part-way through and it corroborates some things or adds to things we already know."
He added that the police service was experiencing ever-increasing challenges in defending the country from attacks, with terrorists using encrypted communication methods, propaganda and more sophisticated methods of violence.
"Now we worry about everything from fairly simple attacks with knives or using vehicles all the way through to the more complex firearms attacks," he said.
"Even though the public are doing a great job, we want more help.
The force has fielded 22,000 anti-terrorism hotline calls since March 2016, double the amount of calls made in the previous year.
"Police have been making arrests at a rate of close to one a day on average since 2014," says Sky News.
The threat to the UK from international terrorism is currently classed as "severe", which means an attack is highly likely. It is one level below "critical", which would mean an attack is expected imminently.