When the UK pushed for measures to ease the workload, and case backlog, of the European Court of Human Rights at the Brighton High Level Conference last month, a key point in the declaration that was adopted by the 47 Council of Europe states' representatives was the principle of subsidiarity. That doctrine, which is long standing but is now to be included in the preamble to the European Convention, essentially involves states parties to the Convention ensuring that Convention rights are secured to people within their jurisdiction, backed by effective remedies at national level.

One might have thought that with such a recent reaffirmation of the role of the court, and the obligations of states parties to the Convention, that governments would be more alert to the need to back up their fine words with actions when it came to observing the court's rulings. Sadly, one of the first to fall at this hurdle appears to be our own Government.

David Cameron's insistence that the UK Parliament can defy the court over prisoners' voting rights, if it results in failure to introduce amending legislation within the six months allowed by the court, would mean the UK forfeiting any claim to the moral high ground it appeared to be maintaining in the run-up to Brighton. How can this country expect other governments to improve their level of observance of the Convention if it wishes to pick and choose for itself when it will give effect to the court's rulings?

It is not even as if the court has left the Government no scope to determine future policy. This week's judgment appears to leave quite a wide margin of appreciation – another principle given enhanced status by the Brighton Declaration – as to which prisoners should be disqualified. It is really rather baffling why the Government should be taking such an absolutist position, which will surely lead to a rash of damages claims being revived before the Strasbourg court once the six months are up. If the Government thinks that will harden public attitudes in line with its own position on Europe, it is playing a dangerous game.

To me, then, Mr Cameron is guilty of a serious failure of leadership, as well as a betrayal of the commitment to the rule of law that should be the mark of any democratically elected leader – a commitment which the Conservative Party, at one time at least, purported in particular to espouse. However there is no point in looking to the Opposition front bench for any better standards. Ed Balls proved himself equally spineless when it came to supporting this most basic of principles.