Local authorities have been warned to prepare for up to three months of disruption in the event of a no-deal Brexit.

Organisations involved in local resilience forums (LRF) have been told to plan to have their multi-agency tactical co-ordination groups on stand-by to determine, co-ordinate and deliver the response if the UK crashes out of the EU without a deal in March.

LRFs have been informed they are likely to have to report to the Government every eight hours and holiday arrangements may have to be suspended over Easter, an indication of how seriously Whitehall is considering the risks.

Resilience forums have been asked to prepare for ‘reasonable, worst case scenarios' - which could include runs on banks, petrol and food – ‘without setting panic'.

A local government source said councils had done as much as possible with limited information from Whitehall.

The source said: ‘Councils are doing what they can with the limited information they are being given.

'We're feeling really nervous and really impatient.'

The codename Yellowhammer has been chosen to act as a shorthand for the 12 work streams across Government, with a local risk assessment to be carried out for each one.

All LRFs have been brought into the planning and preparation process after the Government released a raft of technical papers focusing on the impact of a no-deal Brexit.

Although the no-deal papers dealt with how ports and trading standards should adjust their processes when EU goods are treated as third party goods, they failed to consider the detail of delivery and capacity issues for councils.

A Local Government Association report read: ‘Councils are increasingly concerned about the possibility of a no-deal on Brexit, and are stepping up their work with businesses to ensure that they are as well prepared as possible and can make the necessary investments if needed.'

The Ministry of Housing, Communities and Local Government (MHCLG) is expecting to have to rely on ‘internal reprioritisation' as a first resort to cover the costs of no-deal withdrawal but Downing Street has stressed that frontline spending will not have to be cut.