Lord Sumption:

I do not think there is any case, even in an emergency, for giving legal force to guidance. In almost all countries, and certainly in Ireland and the UK, the Minister makes these rules by regulation. If the Minister wants to give them legal force, he or she can do it by making a new regulation. Therefore, if the Minister wants their guidance to have legal force, they must express it in pure language that citizens can understand and do so in a regulation. It cannot possibly be good enough that something vaguer, say, guidance given at a press conference, be given the force of law because one of the essential elements of law is that it must be possible for the citizen to find out what the law is. For the citizen to look it up, it must be coherently expressed in words which allow for the minimum of confusion. Therefore, on whether there should be a right of power to give legal enforcement to guidance in an emergency, my answer is "no".

On necessary travel, there are serious practical difficulties in defining what travel is necessary as it would differ from one individual to the next. The law necessarily operates in blocks, it is a one-size-fits-all mechanism. I find it very difficult to understand how one could define the necessity of travel with any precision in something that was ascertainable as a matter of law or regulation.