LONDON — Boris Johnson was meant to be doing a Brexit victory lap of the House of Commons this week; instead he stands accused of deserting his post during his premiership's first international crisis.

The prime minister was expecting to return from the private Caribbean island of Mustique to enjoy a post-election honeymoon, taking Britain seamlessly out of the European Union by the end of January.

Instead, five days after U.S. President Donald Trump ordered the targeted killing of top Iranian general Qassem Soleimani, and as Iran retaliated overnight by launching missile attacks on bases in Iraq housing U.S. troops, Johnson is facing questions about why he opted to remain on his tropical paradise holiday until Sunday. And why he has not yet been seen in public during the escalating Middle East crisis.

Labour leader Jeremy Corbyn taunted the prime minister for "hiding behind" his Defense Secretary Ben Wallace, who set out the government's position in the House of Commons on Tuesday.

On the BBC's Newsnight program on Monday, Downing Street’s former national security adviser Peter Ricketts accused ministers of being blindsided by the crisis.

It is not the first time that Johnson has faced criticism over his handling of sensitive relations with Iran.

“I think the British government were caught short by this,” he said bluntly. “People were still on holiday, and there wasn’t sufficient early recognition at the top level that this is a serious crisis and really dangerous for Western interests in the Middle East. I think the reaction could have been quicker."

It is not the first time that Johnson has faced criticism over his handling of sensitive relations with Iran. His diplomacy skills were widely criticized during his time as foreign secretary, but his most tangible gaffe was over the imprisonment of dual British national Nazanin Zaghari-Ratcliffe in Iran. He wrongly told a House of Commons committee that she was "teaching people journalism" while in the country, prompting accusations he had made it much harder to secure her release.

Keep quiet

The lesson from that mistake might have been that the less Johnson says, the better — particularly when he is trying to walk a fine diplomatic line between the hawkish U.S. position and his more cautious European counterparts.

According to officials familiar with the thinking in Downing Street, the prime minister's decision to delegate the foreign policy spotlight to other Cabinet ministers — leaving Foreign Secretary Dominic Raab to do the flagship media interviews and Wallace to face MPs in the Commons — is deliberate. It is also a sign of things to come.

The prime minister will make domestic priorities such as the U.K.'s public health care system, the National Health Service, and rebalancing the economy toward the north of England and the Midlands his public focus, according to one official.

The prime minister's spokesperson pointed out that Johnson — who chaired a Cabinet meeting Tuesday — has spoken to world leaders, and overseen the government's actions, adding that "the response to events in the Middle East is a collective Cabinet response."

Johnson will also discuss the situation at a meeting with EU Commission President Ursula von der Leyen on Wednesday afternoon.

Wallace announced on Tuesday that U.K. forces have been put “on standby” to assist in the Middle East and Royal Navy vessels have been sent to accompany ships through the Strait of Hormuz amid the rising tensions.

But it was Raab who responded to the ballistic missile attack by Iran on airbases in Iraq where coalition forces are stationed, issuing a statement condemning the action. “We urge Iran not to repeat these reckless and dangerous attacks, and instead to pursue urgent de-escalation,” he said

Former Minister for the Middle East Alistair Burt said the perception in the Foreign Office was that the prime minister was in fact "taking [the crisis] really seriously."

"In a way, it is rather a good thing [that Johnson has not taken a big public profile]. The last six months have been all about Boris. It isn’t all about him. This is something where he says 'I’m not going to be driving a bulldozer through every wall you can see, I am going to lead a team'," said Burt, referring to a less-than-subtle Tory campaign stunt in December.

"Maybe that is something the public ought to hear and it is maybe a good thing," he added.

Hard choices

Brexit, though, means that some big strategic decisions will be impossible for the prime minister to avoid.

"Now is the time we are going to see more and more choices having to be made by the U.K. There is Brexit happening in the next few weeks, there are a number of security decisions in terms of the deployment of troops in Iraq together with the coalition. All of that is going to showcase where the U.K. will stand — and whether it is more closely aligned to the EU or more closely aligned with the U.S.," according to Aniseh Bassiri Tabrizi, a research fellow at the Royal United Services Institute for Defence and Security Studies.

Dominic Raab will travel to Washington later this week to discuss the crisis with his opposite number, but Tabrizi warned that aligning too closely with the White House risks making the U.K. more of a target at a time when Tehran has vowed "harsh revenge."

Corbyn highlighted one of those choices in the Commons on Tuesday, accusing the prime minister of being "scared to stand up to President Trump because he has hitched his wagon to the prospect of a toxic Trump trade deal."

So far, the U.K. government has avoided alienating its partners on both sides of the Atlantic. Raab has stressed that the U.K. understands why the U.S. killed Soleimani, insisting that it "had a right to exercise self-defense" — a more supportive tone than from some other European capitals.

"This is probably a way to please the Americans as much as possible, especially in light of [U.S. Secretary of State Mike] Pompeo's criticism in terms of the lack of support from the E3 [France, Germany and the U.K.]," according to Tabrizi. Pompeo's gripe was that, “Frankly, the Europeans haven't been as helpful as I wish that they could be."

Raab will travel to Washington later this week to discuss the crisis with his opposite number, but Tabrizi warned that aligning too closely with the White House risks making the U.K. more of a target at a time when Tehran has vowed "harsh revenge."

But Burt denies that Johnson will slavishly follow Washington's line. He points out that the prime minister has been willing to run against U.S. foreign policy in the past — for example over the U.S. decision to open an embassy in Jerusalem and his continued support for the Iran nuclear deal after Trump withdrew his support.

"For all his contact and closeness with the United States, he was very firmly on the side of British interests being different to the Americans and saying so," Burt said.

With such a seemingly black and white view of allies and enemies in the White House, though, that may prove hard to maintain.

This article has been updated with additional information.