For the first time, the Conservative party has threatened to take the UK out of the European human rights convention. The text of the convention will remain law in the UK because it would be included in a new act of parliament, but it would be “clarified” to remove some existing rights. People in Britain would also lose the right to take the British government to the human rights court in Strasbourg, a right they have enjoyed since 1966.

The Conservative plans, outlined in an eight-page paper, throw down the gauntlet to the Council of Europe, the 47-country body that enforces the convention. Either the council accepts that the policy is a legitimate way of applying the convention, or the UK will withdraw from it.

What is the Conservative policy? It is, as expected, that adverse rulings from the human rights court will be merely advisory. They would become binding only if parliament agreed in each case. Article 46 of the convention says, however, that member states “undertake to abide by the final judgment of the court in any case to which they are parties”. In other words, member states are currently bound by court rulings.

Nobody at the human rights court or the Council of Europe can grant the “recognition” that the Conservatives seek, but they may seek to “engage” with judges and officials. An amendment to article 46 would require the consent of all 47 member states.

It would be fanciful to suppose the UK would be granted special treatment, even though it contributes 10% of the council’s budget. If Westminster has a veto on Strasbourg’s decisions, the parliaments of Russia, Ukraine and other countries will want one too. Making compliance with court rulings voluntary would undermine the entire convention system.

So Britain would “be left with no alternative but to withdraw from” or “denounce” the convention, giving the six months’ notice required by article 58 and delaying implementation of its new legislation until the deadline expires. The paragraph in article 58 saying that countries remain bound by existing adverse rulings, such as ending the blanket ban on voting by prisoners, would be quietly forgotten.

Would the UK be allowed to remain in the Council of Europe as the only country not bound by the convention? Senior Conservatives apparently hope so. They would rely on the fact that the UK had re-enacted the convention in its own laws, but they would remove many of the protections it now provides. Other Council of Europe states are unlikely to be impressed.

No country has yet joined the EU without first joining the Council of Europe, but senior Conservatives are confident that withdrawal from the council would not mean the UK would have to leave the EU. They believe that domestic protection for human rights would be good enough. We shall see.

The Conservative plans are legally coherent, but they would take the UK back half a century to the days before the convention became enforceable by individuals. Judges would just have to do their best with the laws they were given.

Depriving people of their rights does seem to be something of an overreaction to one or two adverse rulings from the human rights court. Surely it would be simpler just to allow a few more prisoners the vote?