Canadian prime minister says Alberta ‘essential’ to country as separatists push for independence

Judge rules initiative to force binding vote on secession invalid as Alberta premier calls for referendum on matter

The Canadian prime minister, Mark Carney, has said that Alberta is “essential” to the country’s future, hours after the province’s leader moved the oil-rich region closer toward a referendum on independence.

Separatists in the western province spent months collecting signatures seeking to trigger a binding October vote on seceding from the nation.