British bobbies have been ordered to ditch uniforms when off-duty and be extra careful on social media websites amid fears of a Lee Rigby-style terror plot to murder a cop.
The Security Service (MI5) has informed the police of a specific plan by Islamic fanatics to kill one or more police officers on the streets of the UK.
It is feared jihadists are monitoring officers online in preparation for an attack.
The intelligence prompted police to raise their internal threat level last month from “moderate” to “substantial”.
Senior officers at the Met, which takes the lead on national policing matters, are instructing officers on the ground to keep a low profile outside of work.
The guidance includes advice on what to wear when coming to work and ensuring social media accounts do not reveal personal information.
A police source told the Mirror: “A raised threat level means officers have to be extra vigilant in everything they do.
“It means not travelling to work in full uniform and standing out unnecessarily out of work.
“Officers are also being warned about putting sensitive information about theirpersonal lives on social networking sites such as Facebook, Twitter and Instagram.”
Thousands of police officers are now having to arrive early for their shift to change into their uniforms in work.
The source said: “Police officers are frustrated at having to turn up early in what’s called ‘half and halfs’, which is usually just wearing the regulation trousers with casual clothes on top.
“It means having to get to the station much earlier to start their shift.
“Many uniformed officers would turn up at the station just before their shift started in full uniform
“Now they have to spend time in the locker room getting ready, which adds time onto their average working day for no extra pay.”
The guidance echoes instructions issued by military commanders following the murder of Drummer Lee-Rigby on the streets of Woolwich.
He was attacked in May last year by two Islamic fanatics wielding cleavers and knives after being spotted walking to his barracks in a Help for Heroes hoodie.
Orders were issued, but later rescinded, that “uniforms should be concealed while in a public place, particularly when travelling alone or from home to unit.”
The new rules will apply to more than 200,000 officers across the country.
Listening station GCHQ has picked up terrorist “chatter” on the subject of targeting a British police officer–seen as a symbol of the establishment.
MI5 is now examining intelligence that scores of personal social media profiles of police officers are being monitored by jihadists in order to glean information about their personal lives.
A series of arrests were made in October on a group of UK-based IS jihadists who were monitoring the Instagram accounts of four police officers.
Officers are currently given guidance on the responsible use of social networking sites.
ACPO released document last year called “Guidelines on the Safe use of the Internet and Social Media by Police Officers and Police Staff” which warns against revealing personal information.
Section 8 of the report relates is headlined Keeping Your Private Life Private, advising officers that “criminals and others may seek to use the Internet and social media to identify personal information about police officers”.
It also says that police officers “in rural locations, in sensitive posts, with uncommon names, or in high profile posts are particularly vulnerable to such attempts”.
Officers are also advised not to use Location Based Services (LBS), which allow social media users to “check in” to a particular location, giving away where they are.
Despite the warnings, hundreds of officers across the country have not applied basic privacy settings to their social network accounts leaving themselves vulnerable.
Security expert Neil Doyle said: “It makes perfect sense that terrorists would be using social media to scout for targets.
“Other criminals such as burglars are known to monitor online chatter to see who in a particular area might be out for the evening or has gone on holiday.
“They can then break into those houses knowing that the risk of them being discovered by the occupants is minimal.
“The use of social media is almost ubiquitous and police forces have embraced the trend in order to appear to be more transparent, with the use of Twitter accounts being a case in point.
“It is not unusual to see officers giving a real-time commentary on their activities during the day in order to give the public an insight into how they work.
“Police officers, however, were warned last month that there was a heightened risk to their personal safety because of terrorist activity.
“The risk is that officers and PCSOs giving away precise details of their movements and routines may leave them open to being abducted by fanatics.”
Preachers of hate have recently been using social media to try and fan the flames of ill-feeling towards police, particularly officers from ethnic backgrounds.
A propaganda booklet circulated by Anjem Choudary last week claimed that it is forbidden in Islam for Muslims to join the police or the armed services.
David Cameron spoke out last week about firms such as Facebook, Google and Twitter having a “social responsibility” to take down extremist material.
In a speech to the Australian parliament in Canberra, Mr Cameron said the West faced a “new and pressing challenge” in filtering out extremist propaganda designed to radicalise impressionable youngsters.
National Policing Lead for Counter-Terrorism, Assistant Commissioner Mark Rowley, has previously said how a warning had been issued “informing our officers and staff of the heightened risk and reminding them to remain vigilant and alert to any possible dangers”.
He added: “All police forces constantly review their security and safety procedures and this will, of course, continue.
“You will see no major changes in the way we continue to police the UK and engage with our communities–our emphasis is on vigilance.”
An ACPO spokesman said: “We are constantly reviewing our security and safety procedures to ensure that police officers and staff have appropriate and up-to-date guidance on how to keep themselves safe from harm.
“We are asking them to follow existing policies and good practice. Our emphasis is on vigilance and remaining alert to any possible dangers, on and off duty, which includes personal use of social media.”