While England was awash with the cross of St George, Gordon Brown chose last week to announce the minting of a new coin to celebrate the Act of Union of 1707 that brought England and Scotland together. The Union Jack flies above 11 Downing Street and the chancellor has made it clear that he supports England in the World Cup, adding the dubious claim that two-thirds of Scots share that view.

In fact Brown knows that his enthusiasm for Sassenach success goes down badly at home. He has compounded the offence by praising the goal scored by Paul Gascoigne that helped to end Scottish hopes in the Euro 96 competition. The remark exhibited a magnanimity rarely associated with the chancellor.

Why is this risk-averse man, a politician to his fingertips, alienating his Scottish constituency? Because an English backlash against Scottish devolution could make it highly controversial for an MP from a Scottish seat to become prime minister, and English discontent may dominate Brown’s tenure in No 10. The forces unleashed could terminate the union. Labour would find it difficult to win a majority in the English parliament that would then emerge, among other consequences.

The problem arises because Labour’s devolution of power to Scotland, like its reform of the Lords, is half-baked. North of the border, members of the Scottish parliament legislate on issues such as health, education and transport. But the members elected from Scotland to Westminster vote on such matters for England, even when the legislation does not affect their own constituents.

The so-called West Lothian question (named because it was first raised by Tam Dalyell who represented that seat at Westminster) will not go away. It is even more prominent because with a smaller majority than before Labour may from time to time need the votes of Scottish members to carry bills that apply to England alone.

John Reid, who appears daily on our television to hector English civil servants, judges and the public, is unmistakably Scottish. His ranting serves to remind us that two of the great offices of state are now held by MPs from Scotland. But whereas the chancellor has responsibility for the United Kingdom economy, the home secretary has only limited powers north of the border.

The full implications of having a prime minister from Scotland have probably not yet impinged on the public mind. But when Brown occupies that position he is likely often to be put on the back foot as he makes policies that do not affect his own voters in Kirkcaldy.

It is painfully apparent that the greatest talents in Scottish politics are not content with running their own country of 5m people. They prefer to rule the 60m who make up the UK, enjoying the sway in international affairs that Britain as a whole carries.

If the opinion polls were translated into an election result there would be a high chance that Labour would have enough seats to form a UK government again, but would have less seats than the Conservatives in England. So a Scottish prime minister would wheel out Scottish MPs to vote down that English Tory majority.

It is hard to see how the present “settlement” between England and Scotland can last. Lord Baker, a Conservative peer, has proposed legislation that would oblige the Speaker in the Commons to decide for each bill whether the Scots should have a say on it. At the last election the Tories pledged to disbar MPs with Scottish seats from voting on English matters, and that is one Michael Howard policy that David Cameron will not disown.

Labour warns that such a change would create two classes of MP. So it would, and perhaps the party should have thought of that before embarking on its devolution course. Brown will be thinking that the prime minister could scarcely be chosen from the B class of parliamentarian.

The balance of terror has shifted. The English used to be worried that Scotland would break away. The Tory party was against it because its full title was Conservative and Unionist. When Britain felt economically inferior to Germany and France the English worried that they would count for still less if they lost part of their population, and they feared that the Scots would make off with North Sea oil and gas.

All that has changed. The Tories see the West Lothian question as a good stick with which to beat Brown. In the longer term their chances of holding office would be better if England bade farewell to Scotland. Britain today is growing faster than its large continental rivals, and the loss of a twelfth of our population in a region that drags down our national performance could not harm us. Our hydrocarbons are less of an issue now that they are being exhausted.

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