The Army arrived in Sellafield this afternoon to maintain protection at the site now the national terror threat level has been raised to critical.

Officers from the Civil Nuclear Constabulary (CNC) based at Heysham are being deployed elsewhere in the country, as part of a government-led operation, following Monday's attack in Manchester.

The Army's arrival locally will be supporting the movement of those CNC officers.

This is part of 'Operation Temperer', which kicked in when Prime Minister Theresa May raised the threat level to critical last night.

It's a scenario that sites such as Sellafield have planned for and exercised in the past. Similar arrangements are also in action at Heysham's power station in Lancashire.

The army work alongside civilian guards in the same was as CNC and will not mean any changes to the usual access arrangements and levels of security checks for workers.

A memo, sent to staff at Sellafield, said: "This is a scenario which Sellafield Ltd, CNC and the MoD has planned for and exercised in the past.

"It is not due to an escalation of the perceived threat to the site, it is a resourcing solution as protection levels are escalated in civilian areas across the country."

The operation will put thousands of soldiers on the street.