People in Hull and Scunthorpe urged to become "counter-terrorism citizens"
Police want us to act as "counter-terrorism citizens'' to help them stop deadly attack plots.
Security chiefs say information from the community is crucial to confronting the unprecedented threat - with more than 6,000 tip-offs yielding useful intelligence last year.
Launching a fresh drive to encourage reporting of suspicious behaviour or activity, Britain's new counter-terror police chief urged people to trust their instincts.
Head of Counter Terror Police North East, Detective Chief Superintendent Martin Snowden, which covers activity in Leeds, said, "Your assistance is more important than ever
"The key to tackling the growing threat from terrorism is our (the police) relationship with, and the support of, local communities.
"Any piece of information you may have could be important. Anything you have seen or heard, anything that your instincts tell you isn’t right, please report it. Specially trained officers and staff will take that information and ensure that it is dealt with in the most appropriate way.
"Your decision could help the police prevent terrorism and save lives"
New figures show that 30,984 reports were made to counter-terror police online or over the phone in 2017.
Of those 6,659 - more than a fifth (21.5%) - resulted in information used by officers to inform live investigations or help build an intelligence picture of an individual or group.
Police are releasing a new film and more detailed guidance on the types of behaviour they want the population to look out for as they launch the latest phase of the Action Counters Terrorism campaign.
Examples of suspicious activity could include hiring large vehicles or buying a large amount of chemicals, fertilisers or gas cylinders for no obvious reason.
Receiving deliveries of unusual items, looking at extremist material online, taking photos of security arrangements or going travelling for long periods without specifying the destination, could also be noteworthy.
Polling indicates that more than 80% of people are motivated to report suspicious activity or behaviour.
Since the start of last year police have foiled 10 Islamist and four right-wing terror plots.
Thursday marks a year since the Westminster atrocity - the first of five attacks that took place in less than six months.
Police and MI5 are running more than 600 live counter-terror investigations relating to 3,000 individuals.
There is also a wider pool of 20,000 former subjects of interest'' who have previously featured in probes and who are kept under review.
Suspicious activity or behaviour can be reported by calling 0800 789 321 or visiting www.gov.uk/A