It is famously hard to pick a fight with Canadians, but Saudi Arabia’s forceful crown prince Mohammed bin Salman is not a man to be held back by what others think. That trait has led to both reforms (allowing women to drive) and a crackdown on those advocating them (arresting women who campaigned for the right). When Ottawa responded by calling for the immediate release of peaceful activists, including Samar Badawi, who has family in Canada, Riyadh lashed out at what it called reprehensible interference in its internal affairs. It expelled the Canadian ambassador, cancelled flights to Canada, froze new trade and investment, and is reportedly selling Canadian assets. Some measures – withdrawing students, and transferring home patients currently undergoing treatment – seem more damaging to those Saudi citizens than their hosts.

This absurd overreaction reflects the bullishness of the man who led the charge to war in Yemen and the blockade which has failed to bring Qatar to its knees as planned. But he has surely been emboldened by Donald Trump’s embrace, and the US president’s own attacks on Canada. It was little surprise when the state department said it would stay out of this row; more disappointing is the reticence of others. The UK has merely urged restraint on its two “close partners” and said it regularly raises rights concerns, including recent arrests.

Riyadh is sending a message to others, and while these measures are harsh, they are not entirely unprecedented: German businesses have reportedly paid for Berlin’s criticism of Riyadh’s role in Lebanese politics last year. It is in European countries’ own interests to stand together and tell the crown prince that such actions are not cost-free for Saudi Arabia. Like his anti-corruption coup, they are unlikely to reassure potential partners; and his mission to modernise the kingdom will require foreign support.