Britain said cars, Scotch whisky and confectionery would be cheaper to sell in Australia because of the agreement, which removes tariffs and reduces red tape. Australia said it was a "great win" for Australian agriculture.
Not surprising, British farmers oppose the deal.
Canadians will be watching closely as Britain negotiates a new deal with Canada, including efforts to increase cheese exports to Canada.
The New Democratic Party has proposed legislation to bar Canadian negotiators from granting any more dairy-industry trade concessions.
Britain has also applied to join the Trans-Pacific Partnership.
The deal with Australia is the first bilateral trade accord Britain has negotiated from scratch since leaving the EU last year.
"I think this is important economically, there's no question about that ... but I think it's more important politically and symbolically," British Prime Minister Boris Johnson said.
"We're opening up to each other and this is the prelude to a general campaign of opening up around the world."
