Why has a leak inquiry been launched into Hermer’s legal advice?

I have now been told by four people in government that a leak inquiry is being conducted into the revelations in last week’s magazine that Lord Hermer, the attorney general, had written legal advice on the American bombing of Iran which made it difficult for Keir Starmer to support attacks to degrade Iran’s nuclear weapons programmes. I quoted a source who had seen the advice as saying: ‘The AG has concerns about the UK playing any role in this except for defending our allies.’

Others who followed up my piece suggested that if the Americans asked the government for permission to use the Diego Garcia base in the Indian Ocean to launch their bunker busters, it might have to be declined, since Hermer does not believe it fulfils the doctrine of self-defence.

Launching a formal leak inquiry is a curious decision. This is not least because the number of people who knew about the gist of the legal advice includes most senior people at the centre of government, a large number of relevant ministers, advisers and officials. This was not a ‘tight hold’.

I saw Hermer on Tuesday evening at the independence day party thrown by the new US ambassador in London, Warren Stephens. He professed to be perfectly calm about my reporting and declared: ‘I’m just getting on with the job.’ Others, however, say he is hopping mad. ‘He is not calm at all,’ one of my spies reports.

One explanation for the leak inquiry is that Downing Street and its chief law officer are firing a warning shot across the bows of anyone who might be tempted to leak the actual text of the legal advice. The reason for this is that it is apparently very wide ranging and, if Starmer adheres to it, it could tie Britain’s hands in future crises.

In writing his views of what was impending in Iran, Hermer apparently tried to put down a marker. ‘It was an attempt to say “this is our settled view of international law” beyond the current situation,’ one official explained. Hermer, as he has repeatedly stated publicly, believes international law is not (as most politicians believe) a matter of interpretation and convenience, but something which is clear, inviolate and always trumps domestic legislation and the will of parliament.

Such an absolutist stance was wholly predictable when Hermer was appointed. But taking it now could make it highly problematic to launch what ministers might regard as necessary military action unless the threat was of such pressing imminence that even the attorney general was satisfied it was legal.