Leading article: Cameron plays the populist card

Over the past fortnight, two instances relating to the rights of unpopular minorities have attracted the ire of the Prime Minister.

First, the ruling under the European Convention on Human Rights (ECHR) that a blanket ban on voting for prisoners should be reconsidered. David Cameron, who said last year that the thought of giving prisoners the vote made him "physically sick", encouraged MPs to express their distaste for the ruling in the House of Commons, which they duly did.

Then the Supreme Court, applying the ECHR, ruled that it was a breach of offenders' human rights for them to be on the sex offenders' register for life with no chance of review. This time Mr Cameron permitted Theresa May, the Home Secretary, to declare that she was "appalled" by the decision, before asserting that he would do the "minimum necessary" to comply with it.

Mr Cameron's response to both judgments is wrong. Giving some prisoners the right to vote could be a fruitful means of aiding their rehabilitation. And Home Office research suggests that 75 per cent of sex offenders monitored for 21 years were not reconvicted of any further offence. Removing from the register those who are no longer a threat is eminently sensible.

But being wrong is one thing. Appealing to the baser instincts of the public is quite another. The Human Rights Act 1998, under which British judges administer the ECHR, came into existence thanks to the votes of MPs. In October 2009, Mr Cameron said repealing it was his third-highest priority. But so far, his mooted reform – a British Bill of Rights – is merely awaiting review by committee. If Mr Cameron doesn't like laws passed by our elected representatives, he should attempt to repeal them, rather than pick fights with judges.

In using the ECHR as a means of expressing solidarity with his recalcitrant backbenchers and the populist press, Mr Cameron is elevating low politics above justice. The chief virtue of the ECHR is that it protects unpopular minorities from just such cynical populism. Mr Cameron should recall that the Convention was established largely at the instigation of a Conservative predecessor who well understood the national interest – Winston Churchill.