A RAISED terror threat level led to a surge in the number of armed police officers manning the streets of Oxford this weekend.

The threat was upgraded from severe to critical, meaning an attack is expected imminently, after a device was detonated at Parsons Green Tube station in south-west London on Friday.

A spokesman for Thames Valley Police said people should expect to see an increase in armed patrols, particularly in high footfall areas.

The force, which would not go into further detail about the number of additional officers and their locations, told the public not to be alarmed by the increased presence.

Armed officers were spotted at the Blenheim Palace International Horse Trials, which ran from Wednesday and concluded today.

The threat level was today lowered to severe.