Britain and Canada are to set up joint diplomatic missions and share embassy offices overseas, British Foreign Secretary William Hague was set to announce on Monday.
The arrangement will see Britain and Canada share consular services in countries where one of them does not have an embassy, a spokesman for Britain’s Foreign Office said.
Reports said that the deal could also eventually involve embassy-sharing with Australia and New Zealand.
Hague and his Canadian counterpart John Baird were to sign an agreement in Ottawa ahead of a press conference revealing more details of the plans.
Queen Elizabeth II is head of state in Canada, Australia and New Zealand as well as 12 other Commonwealth realms and Britain itself.