10/10/2014 13:07 BST | Updated 10/10/2014 13:59 BST

Terror Threat Level Raised For British Police Amid Concerns Over ISIS And British Jihadists

Tim Ockenden/PA Wire
Armed police outside Heathrow Airport's Terminal 4, as airport security was being increased at British airports after the United States called for heightened precautions amid reports two terror networks are working together on a bomb that could evade existing measures.

The terror threat level to police officers and staff has been raised with forces across the UK warned to remain vigilant. Counter-terrorism chief Assistant Commissioner Mark Rowley said officers and staff must be "alert to any possible dangers" as correspondence warning of the risks was sent out.

The senior officer, who is National Policing Lead for Counter-Terrorism, said "The threat level to police officers and staff has been heightened, but we are used to confronting risk and danger, this is what we do on a daily basis, and we are well trained.

"We are informing our officers and staff of the heightened risk and reminding them to remain vigilant and alert to any possible dangers. We are asking them to follow existing policies and good practice. Measures are being put in place to increase the vigilance of officers and staff.

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."

The risks faced by police were underlined last month when terror suspect Abdul Numan Haider was shot dead after stabbing an Australian officer. He launched his attack without warning outside a police station in Melbourne after two officers had arranged to meet him about his cancelled passport.

The decision to raise the level for police officers in the UK comes weeks after the national terror threat level was raised to severe.

Home Secretary Theresa May announced the move amid increasing concerns about Islamic State and the number of British jihadis who have gone to join militants in Syria.