Perhaps sensing weakness on the question of the ‘rule of law’, opponents of the Government’s proposals to protect British troops from ‘vexatious’ prosecutions have launched another salvo this morning.

Several former senior military figures and Conservative politicians, including Dominic Grieve and Sir Malcolm Rifkind, have written to the Prime Minister to claim that the Overseas Operations (Service Personnel and Veterans) Bill is “ill-conceived”. They add that:

“This bill would be a stain on the country’s reputation. It would increase the danger to British soldiers if Britain is perceived as reluctant to act in accordance with long-established international law.”

This follows concerns raised earlier in the summer by Jeffrey Blackett, “Britain’s most senior military judge”, that the Bill will encourage prosecutors to pursue the Armed Forces on international war-crimes charges because it only offers protections against domestic prosecutions. (It also excludes, for now, the campaign in Northern Ireland.)

Now, it seems unlikely that this Government is going to concern itself very much with what Dominic Grieve thinks about anything. But this intervention does highlight just how complex the task of rolling back the growing role of the courts in the military, as in other areas of public life, will prove to be.

It seems quite plausible, for example, that a Bill which limits protection to domestic law does risk a ‘waterbed effect’, with prosecutors simply shifting their efforts to the avenues which remain open to them. But that leaves ministers with an unenviable choice: leave soldiers exposed to vexatious suits here in Britain as a lesser evil, or go further than they perhaps intended in pulling the UK out of the broader international system.

Yet it may be that, in the longer term, such a choice can’t be avoided. The system of “long-established international law” referred to by Rifkind et al is not in fact so very old, and there may be no way to find a sustainable equilibrium between the invariable tendency of lawyers to seek to expand their reach and the understandable desire of political governments to limit it. As international law and the human rights system metastasises from limited protections against the worst abuses into an increasingly comprehensive system, the more conflict there will be.

As for the alleged threat to the reputation of the Armed Forces (amongst the lawyers), ministers must balance this against the need to maintain their efficacy, especially in theatres involving complex, asymmetrical warfare against insurgencies or terrorists. One doesn’t have to be Roger Trinquier to recognise how such adversaries might exploit British troops’ exposure to so-called ‘tank chasing’ lawyers.

Perhaps this time the Government will, once again, back down. Boris Johnson generally gives the impression of a man who has found himself at the head of such forces more by accident than design. But if so it will only be a battle postponed. Tennyson’s vision of a slumbering world, “lapt in universal law”, is falling out of favour on the Right.