A week ago, Sir Mark Sedwill, the Cabinet Secretary, told Parliament’s Joint Committee on the National Security Strategy that media stories about martial law having to be declared in the event of a no-deal Brexit were “complete nonsense”.

He was less categorical when asked about using the emergency powers provisions of part two of the Civil Contingencies Act, saying merely that there was “no plan” to do so. But Sir Mark might not have been quite so sanguine had he been appearing after, rather than just before, the contradictory House of Commons votes on the Prime Minister’s Brexit deal.

Those emergency powers are very broad. They allow Ministers to sign an order that brings into force a “provision of any kind that could be made by Act of Parliament or by the exercise of the Royal Prerogative”.  There are very few limitations. The main one being that they cannot require a person to provide military service – so it would be impossible to introduce emergency conscription.  However, just about anything else is possible.

Parliament would only be asked for approval after the order was in force. There is a seven-day period for this and both the Commons and Lords must agree. If in recess, they must be recalled within five days.

The Act specifically mentions that such powers could be used in the event of disruption to food or fuel supplies. Matters that are clearly worrying the government – hence Chris Grayling’s bizarre recent exercise involving 89 lorries in Kent and the Transport Department’s leaked Operation Yellowhammer plans.

A week ago, the Cabinet Secretary, in trying to reassure people still felt obliged to warn “we cannot fully mitigate all the consequences” of no-deal.  So just in case, “we are doing all the contingency planning that we can” and “there are constant meetings”.

At this point Sir Mark was sounding eerily reminiscent of Sir Humphrey Appleby. At the end of March, we will no doubt discover whether those constant meetings and contingency planning have paid off. But it does raise fundamental questions about the legislation passed 15 years ago and the structures and mechanisms it put in place.

Central to the emergency arrangements are local resilience forums of police, fire and ambulance services together with councils and relevant NHS bodies. Their job is to assess the risk of emergencies in their areas and help put in place necessary plans.

What may have worked back then is now looking rather frayed. Since 2010 local authorities have seen funding halved; we have 20,000 fewer police; and there are now daily pressures in the NHS. Is it any wonder that emergency planning has dropped down the priority list.

There are no minimum standards laid down and no means of knowing the capability of an area to manage a crisis. And we saw what that can mean with the bungled response by Kensington and Chelsea Council to the Grenfell Tower tragedy.

So the real dilemma for the Cabinet Secretary sitting in the COBRA bunker dealing with a national emergency is will they be sending out orders to phantom armies at local level? Sir Mark presumably hopes the issue will not arise on Brexit Day (if and when it finally arrives). But maybe the Cabinet itself ought to make sure that our civil contingency systems are fit for purpose for when such a moment does arise. 

Lord Toby Harris of Haringey is a Labour peer and a member of the Joint Committee on National Security Strategy