Irish officers patrol the border, but forces including London’s Metropolitan police could be called on in the event of prolonged unrest

Ministers have drawn up detailed plans to deploy police officers from English forces to Northern Ireland in the event of a no-deal.

In high-risk or emergency situations, police can be sent to other parts of the UK in a procedure known as mutual aid, previously used during the London riots and the G8 summit in Fermanagh.

Under contingency plans, around 300 Scottish police would be deployed to support the Police Service of Northern Ireland (PSNI) as a preliminary step.

However, if civil unrest or sectarian violence spirals, officers from forces including London’s Metropolitan police could be called on.

According to those briefed on the plans, Kent will place the greatest demand on police resources in Britain as the country’s main gateway to Europe and a