Counter-terrorism police say more than one in five tip-offs from the public provides useful intelligence.
The revelation is being made as part of a national advertising campaign urging people to report suspicions.
Research suggests that while more than 80% of people feel motivated to report suspicious activity or behaviour, many are unclear about exactly what they should be looking for.
Police have released a video highlighting terror attack methods in phase two of the ACT (Action Counters Terrorism) campaign. The film is based on real-life foiled plots and shows examples of terrorist-related suspicious activity.
Head of Counter Terrorism in the North West, Detective Chief Superintendent Dominic Scally, praised the public’s willingness to respond following last year’s unprecedented rise in terrorist activity – saying record numbers of people had contacted the police online or via a confidential hotline.
He said: We want people to trust their instincts and act by reporting in confidence something they feel is unusual or suspicious.
Like other criminals, terrorists need to plan and that one piece of information could be vital in helping us to stop an attack.
We need the help of communities to defeat terrorism and this campaign will inform people of what to look out for and how to report their concerns.
Det Chief Supt Scally said that any piece of information, no matter how small, could make the difference between a lethal attack and a successful disruption.
Examples of suspicious activity could include:
:: Hiring large vehicles or similar for no obvious reasons
:: Buying or storing a large amount of chemicals, fertilisers or gas cylinders for no obvious reasons
:: Taking notes or photos of security arrangements, or inspecting CCTV cameras in an unusual way
:: Looking at extremist material, including on the so-called Dark Web, or sharing and creating content that promotes or glorifies terrorism
:: Someone receiving deliveries for unusual items bought online
:: Embracing or actively promoting hateful ideas or an extremist ideology
:: Possessing firearms or other weapons or showing an interest in obtaining them
:: Holding passports or other documents in different names, for no obvious reasons
:: Anyone who goes away travelling for long periods of time but is vague about where
:: Someone carrying out suspicious or unusual bank transactions
The new campaign comes amid allegations that the Government’s Prevent strategy to turn vulnerable individuals away from extremism is deeply flawed.
The Parsons Green terrorist Ahmad Hassan had been on the programme for more than a year before planting a bomb on a crowded London Tube train.
Dr David Lowe, a former Merseyside Police officer who now works with the Home Office on Prevent, accepts improvements should be made.
He told Sky News: It’s worthwhile rebranding and remarketing it and saying it is about all of us in society. It is about protecting all of us… those who are vulnerable to being drawn in.
Look at the circumstances behind it, what can we do to help them. It’s about helping people and not just about picking on them.