Tip-offs from the public have foiled terrorist attacks on Britain’s streets, the UK’s most senior counter-terrorism police officer has told Sky News.

At the launch of a nationwide appeal for the public's help, Assistant Commissioner Mark Rowley said that 13 potential attacks had been disrupted since June 2013.

Information from the public has contributed to stopping some of those attacks, while figures show it has also helped counter-terrorism police in a third of the most high-risk investigations.

Mr Rowley told Sky News: "It is my belief that without the public's help, some of the terror plots which we've foiled would have been successful."

He said the complexity of the terror threat is greater than ever before - and that the lorry attacks in Berlin and Nice last year were "game changers".


"The stretch is enormous," he said. "You have got this range from, on the one hand, the more sophisticated plots we've seen with ghastly consequences on the continent, through to individuals or pairs who are radicalised largely by propaganda on the internet and look to pick up knives and carry out fairly unsophisticated attacks.

"Covering that range is very difficult and that's why we're appealing to the public. Often we have an incomplete piece to the jigsaw that is our investigation and sometimes it is that extra piece of information from the public that makes the difference."

October: Former MI5 spy reveals foiled terror plots

Mr Rowley said the security services are running more than 500 live investigations at any one time.

In the year to March, the anti-terrorist hotline received 22,000 calls from the public - more than double the number in the previous 12 months.

As part of the Action Counters Terrorism campaign, a podcast has been produced which reveals previously untold stories of how terrorist attacks in the UK were stopped, featuring accounts from detectives, bomb disposal and surveillance officers.

A series of television adverts will also air encouraging members of the public to come forward with information which they might otherwise believe is of little value to investigators.

The Assistant Commissioner said that often the most unlikely piece of information can provide officers with vital clues in their efforts to disrupt terrorist plots.

"Sometimes that public information has actually started an investigation," Mr Rowley said. "Other times it's part way through and it corroborates some things or adds to things we already know.

"The public are making a great contribution which is critical to us all working together to protect ourselves from terrorism."

October: Ex-MI5 officer 'was nearly kidnapped'

Despite foiling a number of plots since the murder of soldier Lee Rigby in May 2013, Mr Rowley stressed that the threat from terrorism remains severe.

On average, police have been making arrests at a rate of close to one a day since 2014.

The official threat level for terrorism has stood at severe - meaning an attack is "highly likely" - for more than two years.

Mr Rowley said "tempo" of activity continues, and identified a host of challenges including encrypted communication methods, propaganda and the range of possible attack methods.

Although the terror group ISIS is losing ground and fighters on the battlefields of Syria and Iraq, Mr Rowley warned that was unlikely to diminish the threat of terrorism facing countries across the West.

A significant proportion of those involved in terrorist activity in the UK are British-born and have never been to the Middle East, but instead were radicalised over the internet, or with small groups of friends.

The authorities are also monitoring hundreds of individuals who have returned from Syria and Iraq.

It is thought that up to 400 are still in the Middle East, and that those who are not killed in the fighting there might attempt to return to the UK in future.