The leaked memos are a cause for concern – not their contents

The point that matters about the leaked cables from the UK ambassador to the US is the leak, not their contents. Boris Johnson, if he is the new Prime Minister, should pursue that vigorously. But he should not pander to President Trump by cutting short Kim Darroch’s tenure.

The contents of the emails leaked to the Mail on Sunday are no more than the kind of views that ambassadors have a right – indeed, duty – to record and send back home. The cables are dated between 2017 and the present, but the most trenchant phrases – about an inept, incompetent and dysfunctional administration – have an air of being a couple of years old when this was standard commentary about the drama, breaches of precedent and defenestrations in the Trump White House.

The tone towards Trump has changed but there is still cause for ambassadorial warnings

Jeremy Hunt, Foreign Secretary and Johnson’s rival for the prime ministership, was too quick to distance himself and the UK from these views. In the first months of Trump’s presidency, the UK was as aghast as many of the US’s closest allies at the indifference or hostility to international agreements and institutions that he expressed, and the sheer unpredictability, hour by hour, of what would come out of the White House beyond its ability to grab the headlines.

But the tone has changed, a bit, from that early incredulity at the sheer drama of it all. That is partly because Trump has moderated some of his early positions, such as the blowtorch of scepticism he turned on NATO. It is also because of his popularity and the strong chance that he wins a second term.

The UK’s desire for an early trade deal after Brexit is certainly in there as a factor. All the same, the inconsistency of Trumpian policy – on North Korea, say, or now China – and difference of views with the UK on Jerusalem, the Paris climate change accord and Iran – are still enough to give any UK ambassador plenty of cause to send warnings back across the Atlantic.

A new prime minister must stand up to Trump’s bullying of Kim Darroch

President Trump will remind Boris Johnson not just of his expressions of personal liking for the probable new Prime Minister but also his offer – without detail – of a trade deal. It will be tempting for Johnson to pander to Trump and cut short Darroch’s tenure, due to end in early 2020.

That would be a mistake. First, any country should stand up against another’s attempts to bully its ambassador – or its government. Trump, in declaring by tweet that he would not deal any longer with Darroch, is attempting just that. What is more, in going on to criticise Theresa May and saying that in his recent visit to the UK he was impressed only by the Queen, he has been far more sweeping in his insults, more personal and more public than anything Darroch said.

The supposed offer of a trade deal is not solid ground, as any trade deal with the US will be driven by raw national interests – as Trump has shown with Canada and Mexico. The US will not be shy of using its power to demand access to agricultural and other markets, and the UK after Brexit – if it has indeed left the EU’s Single Market and Customs Union – will have a stark choice about whether to stay close to the EU’s standards and regulations or those of the US. Many MPs have been disingenuous in pretending otherwise. Darroch’s comments – or Johnson’s apparent personal friendliness with Trump – are unlikely to have any impact whatsoever on these calculations.

A vigorous investigation into the leak must uphold the principles of government

The more important point is the handling of the leak. The fact that these cables were leaked seems very much in the highly politicised spirit of the times, where people feel so strongly about their personal convictions that they feel it is legitimate to break convention (and in this case, possibly the Official Secrets Act 1989). Brexit has brought many examples, including the collapse of the Cabinet’s collective responsibility, and the constant leaks from there.

This is highly damaging to the way that government works. It undermines the ability of civil servants to give advice, particularly when they think a course of action is damaging to the country, if they fear it might be leaked to serve one side or the other by either their fellow civil servants or politicians.

It matters that the Government pursues the source of the leak vigorously, as it did with Gavin Williamson. The former Defence Secretary was sacked by Theresa May for being the source of a leak from the National Security Agency about the Chinese firm Huawei, although he has denied being involved.

The worst outcome would be for Johnson to punish Darroch –  pandering, in effect, to Trump – but fail to conduct the kind of investigation into the leak that would uphold the principles on which UK government runs.