Image caption David Sterling said it might be necessary to "establish new, temporary structures" on a 24/7 basis

The head of the Northern Ireland Civil Service (NICS) has written to all of its 23,000 staff seeking "volunteers" for its contingency response to Brexit.

David Sterling said NICS' preparations include planning for a no-deal Brexit and a "worst case scenario" involving "sustained and widespread disruption".

Mr Sterling asked for volunteers to work in NICS "command, control and coordination structures".

He said "new, temporary structures" may have to be introduced on a 24/7 basis.

However, Mr Sterling added that the plans do not mean that he believes a "no-deal exit is now the most likely outcome, or that it will even be necessary to ever operate these arrangements".

"This is simply the next step in readying our plans for exit day," he explained.

Civil servants expressing their interest in joining NICS's contingency response have been asked to indicate whether or not they would be willing to work shifts and at weekends.

The NICS plan includes a "central hub" that will coordinate the strategic Northern Ireland response to Brexit.

The hub will operate jointly between the Northern Ireland Office and Stormont's Executive Office and may need to be staffed round the clock.

NICS has invited staff from all grades to apply for the new roles.