A spokesman for Durham Constabulary said: “The national security threat level is now critical. We’ve stepped up patrols across County Durham and Darlington to provide a visible, reassuring presence. This will remain the case for as long as necessary.
“There is nothing to suggest there is any specific threat to our communities in County Durham and Darlington. However, we will continue to review public events due to take place in our area over the coming days. We have sent a small number of officers to assist the policing operation in Manchester.
“Durham Constabulary have plans in place for situations like this and currently it is extremely unlikely that members of the public will see military staff on our streets. Please remain calm but alert. If you see anything that causes you concern, then call the anti-terror hotline immediately on 0800 789 321. In an emergency dial 999.”