Boris Johnson's holiday has left him one step behind on the Iran crisis – and risks angering both Trump and Tehran

Previous leaders, from David Cameron to Tony Blair, have fallen foul of an ill-timed break – the prime minister may regret taking his

Boris Johnson is finally back at his Downing Street desk today, after being criticised for his slow response to the dramatic, worrying turn of events in the Middle East.

Johnson decided not to cut short his luxurious 12-day break on the Caribbean island of Mustique after Donald Trump ordered the assassination of Qassem Soleimani, a key Iranian general. Most prime ministers would have returned early, keen to show they were at the helm during a crisis, as David Cameron did from his holiday in Italy during the 2011 London riots. (Cameron’s fingers were burnt as opposition leader in 2007, when he went ahead with a visit to Rwanda despite flooding in his Witney constituency).

Johnson showed he is not a conventional PM. He left himself open to the charge, as Emily Thornberry, the shadow foreign secretary, put it colourfully, of “sunning himself drinking vodka martinis somewhere else and not paying attention to this”. Perhaps Johnson suffered the Caribbean curse. James Callaghan, the Labour prime minister, came under fire for saying “crisis, what crisis?” on his return from a 1979 Guadeloupe summit to industrial unrest at home. (He never said those words, but the damaging headline stuck).

In 2006, Tony Blair declined to return early from St Lucia to face the music after refusing to call on Israel to halt its attacks on Hezbollah in Lebanon. Labour colleagues were furious; the pressure on him to announce his departure timetable became unstoppable. Blair admitted in his memoirs the affair did him “real and lasting damage”. (He argued that PMs never really switch off on their hols, but admitted “somehow, away from it all in a different setting, the weight is easier to bear”).

There were personal as well as political reasons why Johnson took three days to react to this crisis. He and his team were exhausted after not having a proper break since the Tory leadership election began in June. After an exhausting general election campaign, they quite reasonably gave themselves a longer than usual two-week Christmas break. If the election hadn’t happened yet, I suspect Johnson would have made a swifter return to show voters he was on the case.

So the crisis erupted at a bad time for Johnson. Eyebrows were raised in Whitehall at a sluggish response by ministers. Unusually, Sir Mark Sedwill, the cabinet secretary and national security adviser, had to chair three emergency meetings. Johnson did discuss events by phone with Dominic Raab, the foreign secretary, who learnt of the attack via the media; the US did not forewarn its close ally, breaching an unofficial “no surprises” rule, to London’s consternation.

Politically, Johnson’s refusal to come home quicker bought him a little time to plan a very difficult balancing act. Should he back Trump, despite his apparent lack of a thought-out strategy on Iran? Or should he stick with the Europeans, as the UK, France and Germany are still trying to keep alive the flickering flame of the Iran nuclear deal dumped by Trump in 2017?

It’s a bit too simplistic to argue that Johnson will side with Trump because the UK will desperately need a US trade deal after Brexit. London also needs a trade agreement with its biggest trading partner, the EU. It can play a diplomatic card in those talks; the EU, keen to be a player in a world dominated by the US and China, wants to keep the UK in its diplomatic orbit. Cuddling up to Trump would send a bad signal just when Johnson wants a positive start to the EU negotiations.

Inevitably, the prime minister is trying to ride both horses. After the US criticised Europe’s lack of support, Raab toughened the initial response, saying the UK is “sympathetic” to America’s situation.

When he finally broke his silence on Soleimani, Johnson said: “We will not lament his death.” But he took a different line in a joint statement issued just before midnight on Sunday with Germany’s Angela Merkel and France’s Emmanuel Macron. They managed not to mention the US attack but said: “There is now an urgent need for de-escalation. We call on all parties to exercise utmost restraint and responsibility.” Johnson wants to persuade Iran not to abandon the nuclear deal and Iraq not to expel foreign troops, including British ones, while trying to restrain an unpredictable Trump.

Raab, rather than Johnson, is due to make a Commons statement on Tuesday. Perhaps Johnson does not want his dilemma to be exposed so publicly. Perhaps he does not want to be reminded of his role in worsening the plight of Nazanin Zaghari-Ratcliffe, the British-Iranian mother in jail in Tehran.

It was a low point in Johnson’s uncomfortable two years as foreign secretary. If he ever thought he would avoid agonising decisions on foreign policy as PM, he now knows there will be no escape, even when he is on holiday.