POLICE have sought to reassure the public, after anti-terrorism chiefs said another attack may be imminent.

Earlier today terrorists detonated an "improvised explosive device" on a crowded underground train at Parsons Green tube station in West London. The incident injured 29 people, police have said.

This evening, terror experts at the Joint Terrorism Analysis Centre took the decision to raise the national threat level from "severe" to "critical".

It means that a terrorism attack is believed to be highly likely - and may also be imminent.

Troops will be sent to patrol busy streets and there will be heightened security at “high risk” locations, such as airports and major sports matches.

Tonight, Wiltshire Police have sought to reassure members of the public that the terror threat in Swindon remains low.

T/Superintendent Dave Minty said: "There is no known specific threat to Wiltshire and the South West region at this time and it is unlikely that our communities will see a military presence on the streets.

"The most important message is for the public to remain alert but not alarmed – police nationally and locally along with our partners, are doing everything we can to help protect the security of our citizens, public institutions, critical national infrastructure, and businesses and places.

"Communities defeat terrorism, which is why we must maintain the strong relationship between the public and police. We depend on information from the public, who can be our eyes and ears, in our efforts to keep us all safe.

"Our security measures and activities are under constant review and we will keep communities updated.”

T/Supt Minty said that Wiltshire Police's thoughts were with those affected by the Parsons Green incident this morning.

He urged people to remain vigilant. To report suspicious activity, call the anti-terror hotline on 0800 789 321 or, in an emergency, call 999.

For more about reporting suspicious behaviour, visit: act.campaign.gov.uk. For the latest guidance on recognising the terror threat and remaining vigilant, visit:www.nactso.gov.uk.