“Silly and not quite harmless” would be the best verdict to deliver on the Government’s proposed “values” oath for holders of public office. Well-meaning as it is, it has few virtues beyond giving journalists something to fuss about on a slow news day. It may even be more trouble than it is worth. Sajid Javid, the Communities Secretary, says a compulsory public pledge would encourage tolerance and enhance cohesion. It is an odd thing for a Tory to be pushing for.

The most obvious drawback is that the oath would in itself be a denial of one of the basic values it might seek to uphold: the right to dissent. Why should anyone have to sign up to some officially approved list of moral rules if they don’t believe in them? This is effectively the case if their livelihood depends on it. If a soldier or a teacher doesn’t believe in equality, should they be forced to say they do just to hang onto their job? Would it make them better or worse citizens? If they practise acts of discrimination or hate crimes then they should face the consequences. It is difficult to justify their suffering such a detriment to their lives just because they have offensive private views.

Nor would an oath of loyalty be likely to stand the test of time. One framed in 1716 or 1916 would look very different to today’s, just as a 2116 version no doubt would. There is little point in seeking to codify “values” that evolve and flex over time as society changes. Indeed that is the useful thing about an unwritten constitution – such accommodations can shift, without the need always for a violent argument over what previous generations thought immutable.

Slavery, the British Empire and restricting the right to vote to male property owners would once be commonplace “values”, or practices easily derived from the mores of their day. Once upon a time “Christian” values would be the thing: impossible today. British values were not always laudable, especially in the imperial age, and were never enshrined in a solemn pledge by public servants to uphold them. Just as well.

Such pledges never allow for insincerity, or changes of mind. The dedicated racist or neo-Nazi terrorist might have little problem mouthing these banalities for a greater cause, as history has shown. Public oaths guarantee nothing, and it is silly to imagine they do.