Counter-terror chiefs are calling on shoppers and businesses to be their “extra eyes and ears” in the lead up to Christmas.
Senior officers want the public and retail staff to remain vigilant and report any suspicions to help them combat the risk of an attack.
While there is no specific intelligence of an increased threat over the festive period, security measures will be deployed in busy town and city centres.
Chief Superintendent Nick Aldworth, national co-ordinator for the police protect and prepare strategy, said: “As people are enjoying the festive season, they will see a visible security presence with police patrols and additional security in crowded places.
“Unpredictable deployments across the UK will also provide an additional layer of protection, with specially-trained uniformed and plain clothes officers working to deter, detect and disrupt hostile reconnaissance and encourage the public and businesses to be their extra eyes and ears and report anything that doesn’t feel right.”
The Counter Terrorism Policing network is launching its largest ever winter advertising campaign.
Security messaging will be on display at busy Christmas events and key shopping locations to remind the public of the role they can play in helping tackle the terrorist threat.
Police want retailers and other businesses which operate in crowded areas to draw up a “60-second security plan” – a checklist of questions staff should be able to answer.
Mr Aldworth said the measure could “drastically” improve reaction times in the event of an emergency.
Just under a year ago, there were scenes of panic on London’s Oxford Street after reports of gunfire sparked fears of a terror attack.
Armed police were deployed and shops and businesses were placed on lockdown, but officers found no evidence of any shots fired.
Mr Aldworth said: “Last year on Oxford Street, we saw a fight at a Tube station cause panic when people believed that a terrorist attack had occurred.
“In the rush to keep themselves safe, some people suffered serious injuries and businesses were severely disrupted.
“By working alongside those businesses, we have learnt from that experience and I believe that our 60-second check will better prepare us to deal with something similar in the future.”
Police and MI5 are running a record 700-plus live terrorism investigations as they confront a threat that is seen as unprecedented in scale.
Britain was hit by five attacks last year, while 17 plots have been foiled since March 2017.
– Suspicious activity or behaviour can be reported by calling 0800 789 321 or visiting www.gov.uk/ACT