IN PETER SELLERS’ classic comedy, The Mouse that Roared, the tiny Duchy of Grand Fenwick declares war on the mighty United States. It expects to lose but fate, in the form of a special weapon, gives it victory and the headache of what to do next.

Whether tiny Brecqhou, with its knighted millionaire residents, can truly be portrayed as a mouse is dubious – but it has undoubtedly roared.

And it has done so not just at its larger neighbours, Sark and Guernsey, but also at the UK in the form of the Secretary of State for Justice, the Lord Chancellor and, ultimately, the Privy Council.

For the decision announced yesterday to uphold at least part of Sir David and Sir Frederick Barclay’s assertion that the new Sark Reform Law is in breach of the European Convention on Human Rights is a substantial victory.

It is not a conclusive one – appeals are likely by both sides to the Supreme Court of the House of Lords. But the ramifications of the decision will echo down the corridors of power in at least three parliaments.

Firstly, in Sark, it deals a mighty blow to the island’s unelected judge and ex officio president of Chief Pleas. Quite simply, the first task of the new Chief Pleas must be to reform its new government by removing the Seneschal as its de facto speaker.

In Guernsey, the questions thrown up are more complex. The Bailiff, in theory, is similarly compromised by his dual role as chief judge and unelected presiding officer over the States.

However, there are significant differences between the two men’s positions. The Bailiff’s powers in the States have been diluted over the years to the point that it can be argued that they do not fall foul of the convention.

Nevertheless, the debate will be had. At its heart must be the consideration that an elected member of parliament must never be constrained by a presiding officer’s other role.

But lawyers for the Barclay brothers are determined it will not stop there. For them at stake is the whole system of who makes law in the Bailiwick. If they roar again, we may find out.