The meeting could not have been more cordial when Donald Trump hosted Justin Trudeau at the White House in February.

Mr Trump was on his best behaviour and Mr Trudeau oozed charm. The greatest excitement was generated by the Canadian prime minister successfully fending off the US president’s distinctive grab and yank handshake technique with what was hailed as an “alpha shoulder grab”.

The vignette was seen, at least by self-appointed experts on social media, as Mr Trudeau asserting that Canada was not going to be pushed around by its powerful neighbour.

Mr Trump had railed in his election campaign against the North American Free Trade Agreement (Nafta), which he said had put Americans out of work. But his target had been Mexico, rather than Canada, and this was the theme he stuck to when the two men met.

“We have a very outstanding trade relationship with Canada. We will be tweaking it. We will be doing certain things which benefit both of our countries,” the US president said.

“It is a much less severe situation than what’s taken place on the southern border. For many, many years the transaction was not fair to the United States.”

Mr Trudeau stuck to the script, too. “Canadians are rightly aware that much of our economy depends on a good working relationship with the United States, a good integration with the American economy,” he said.