The election in Montreal had been seen as a referendum on Canada’s deeply unpopular prime minister, who has faced calls from within his party to quit.

The loss, coupled with a recent Toronto defeat, signals waning support for Trudeau, who faces a challenging re-election campaign.

Justin Trudeau’s Liberal party. On September 16th the prime minister’s party lost a by-election in his hometown of Montreal, an area that it had represented almost uninterruptedly since the second world war.