If you suspect it, report it - that's the message from Surrey Police as a national counter-terrorism publicity campaign launched this week.

Everyone has a role to play in fighting terrorism and the public are being encouraged to contact the confidential Anti-Terrorist Hotline on 0800 789 321 if they see any activity or behaviour they think is suspicious.

The two-week campaign consists of a 40-second radio advert which is being broadcast across England and Wales.

The threat to the UK from terrorism remains real and serious and public vigilance and awareness is crucial in helping to create a hostile environment for terrorists.

The advert recognises that some people may be reluctant to report suspicious activity or behaviour, such as a person taking an unusual interest in security arrangements, because 'Chances are, it's probably nothing'.

But it goes on to encourage people to think 'But what if it isn't'?

Just one piece of information could be vital in helping disrupt terrorist planning and, in turn, save lives.

Detective Inspector Kevin Jewell, temporary Head of Surrey Police’s Special Branch, commented: “Hardly a month passes without an event somewhere in the world which should act as a stark reminder to us all that we continue to face a real and enduring threat from terrorism. While the attack could be in Surrey it is equally possible that terrorists are living in Surrey and planning their attack elsewhere.

"These groups are constantly looking at new and inventive ways to launch attacks on the UK and our citizens.

"We all know that the threats against us continue to diversify - from Al Qaeda-led and inspired groups, through Irish-related terrorism to right wing extremists.

"The police and security services need the help of the public to protect the country from the threat of terrorism. We cannot do it alone.

"We all have a responsibility to remain vigilant and aware and to report any suspicious activity. We must not become complacent.

"I completely understand that some people may have concerns about contacting police with their suspicions, but they can be reassured that all information received by the confidential Anti-Terrorist Hotline is thoroughly analysed and researched by experienced officers before, and if, any police action is taken.

"I would urge anyone who has information about suspicious activity to contact the Anti-Terrorist Hotline on 0800 789 321."

Police want people to look out for the unusual - some activity or behaviour which strikes them as not quite right and out of place in their normal day to day lives e.g.:

Terrorists need storage - Lock-ups, garages and sheds can all be used by terrorists to store equipment. Are you suspicious of anyone renting commercial property?

Terrorists use chemicals - Do you know someone buying large or unusual quantities of chemicals for no obvious reason?

Terrorists need funding - Cheque and credit card fraud are ways of generating cash. Have you seen any suspicious transactions?

Terrorists use multiple identities - Do you know someone with documents in different names for no obvious reason?

Terrorists need information - Do you know someone taking an interest in security, like CCTV cameras for no obvious reason?

Terrorists need transport - If you work in commercial vehicle hire or sales, has a sale or rental made you suspicious?

IF THE PUBLIC NOTICE SUSPICIOUS BAGS, BEHAVIOUR OR VEHICLES WHICH POSE AN IMMINENT THREAT THEY SHOULD CALL 999 IMMEDIATELY

Call 0845 125 2222 for all non-emergency policing matters.

Call 999 if you have a genuine emergency requiring the attendance of the police (eg a crime is in progress or someone is in immediate danger).

Call independent charity Crimestoppers on 0800 555 111 if you have information about crime and don't want to leave your name.