The pooling could mean, for example, that a proposed Australian consulate to be opened on Phuket could service citizens from all four countries eventually.
What's clear so far is that Britain and Canada will establish joint diplomatic missions and share embassies abroad, as the British foreign secretary is due to announce at any moment.
Foreign Secretary William Hague will begin by outlining plans to share embassy facilities in countries where neither Britain or Canada has one already when he meets John Baird, the Canadian foreign minister, in Ottawa.
The British foreign secretary described the countries as ''first cousins'' under one queen and united by a set of values.
''We have stood shoulder to shoulder from the great wars of the last century to fighting terrorists in Afghanistan and supporting Arab spring nations like Libya and Syria,'' he said on Monday morning.
''So it is natural that we look to link up our embassies with Canada's in places where that suits both countries. It will give us a bigger reach abroad for our businesses and people for less cost.''
A Foreign Office spokesperson said the process involved ''colocating'' embassies at this stage. But already in Canada, critics are questioning whether such an arrangement might curtail the ability of Canadian diplomats to act independently in some countries.
The British Foreign Office is looking for ways to extend its reach at a lower cost as the government tries to cut public spending.
As early as 2009, some embassies had to ban hospitality and impose pay cuts on local staff in a bid to prevent a budget crisis, the Financial Times reports.
One British diplomat put it more bluntly, according to the Daily Mail: ''For all the grandiose talk of European unity, we have so much more in common with many Commonwealth countries than the EU - and not just the English language.
''There is a saying in the British diplomatic corps that 'the French want to do us over, the Germans want to lord it over us and the Italians are all over the place'.
''We would never dream of trusting them with intelligence secrets, but we share everything with the Canadians, Aussies and Kiwis.
''Brussels can extend its diplomatic reach - well, so can we.
''The EU is so burdened by history it doesn't know what it wants to do and is hopeless at speaking with one voice.
''We Brits know who we are, who our real friends are, and between us we have been a rather good influence on the world in the past century.''
Queen Elizabeth II is the constitutional monarch of 16 sovereign states and their territories and dependencies, as well as head of the 54-member Commonwealth of Nations.
It's not expected that Britons, Canadians, Aussies and New Zealanders will feel obliged to agree on everything on Phuket anytime soon.