With the terror threat becoming increasingly complex and varied, police are calling on communities to act on their instincts to help prevent atrocities taking place in the UK and overseas.
The appeal comes as new figures reveal information from the public has assisted counter terrorism police in a third of their most 'high-risk' investigations, helping keep communities safe.
The UK's most senior counter terrorism officer, Assistant Commissioner Mark Rowley, will launch a new Action Counters Terrorism, or ACT, campaign today (Monday 6th March) - urging the public to report suspicious activity to the police.
Mr Rowley will tell an audience of community and business representatives in Manchester that information from the public continues to play significant part in recent successes in countering terrorism. However, officers need even more information to help build better intelligence pictures on individuals or groups plotting attacks.
This comes as the threat, which remains 'Severe' - meaning an attack is highly likely - continues to diversify and expand. This is seen in cases where terrorists have been able to reach across the world to radicalise often vulnerable, volatile or chaotic individuals and groups, and inspire and direct them using instant and secure communications.
Mr Rowley says: "It is very encouraging that in a third of cases involving our most serious terrorist suspects we have benefited from information from the public. The number or calls and online reports we receive is also increasing. This is a testament to the trust people hold in policing - but now we are appealing for even more.
"Counter terrorism policing and the security and intelligence services are working tirelessly to keep the public safe and together we have stopped 12 attacks since the summer of 2013. However, advances in technology make it more complex and challenging for us to spot would-be terrorists because it's easier for them to be in contact with others and be radicalised in a relatively short space of time using encrypted communications.
"The threat is becoming more varied and the move towards low-tech attacks on crowded places, like those we have seen in major European cities and beyond, makes it even more important everyone remains vigilant and acts, by calling us confidentially, if they are concerned about suspicious activity."
Last year a record number of people contacted the confidential Anti-Terrorist Hotline, with the service receiving more than 22,000 calls. Officers hope this number will continue to increase if more can be done to encourage people to call or report online.
Research to support the ACT campaign looked at public attitudes towards CT policing. Over 80% of respondents said that it was important for communities to work with police to prevent terrorism. However a quarter of those surveyed said they might not report their suspicions because of fears over wasting police time and 39% were unsure about what suspicious behaviour might look like.
Mr Rowley adds: "Our call and report numbers are increasing and research has shown many people want to play their part, but some people worry they might be wasting our time or they are not sure what sort of activity might be suspicious. So we want to allay those concerns and help them to help us make nothing happen."
More information on what to look out for and how to contact police can be found at gov.uk/ACT or call by calling police confidentially on 0800 789321.