It will be the most unwelcome uniformed incursion from south of the border since Culloden, according to some Scots.

But the 6,000 English and Welsh police officers helping to provide security at next month's G8 summit at Gleneagles will have to do more than watch their step on the Perthshire hills.
They are being given a crash course in Scots law to ensure any action they take in the line of duty does not end up the subject of fresh battles in the courts.