British negotiators withdrew from trade talks with Canada today, Thursday, a dramatic development that disrupts the bilateral trade agreement between the Commonwealth countries that has been in preparation for years.

The main point of disagreement is the extent of access that producers in the United Kingdom should have to the Canadian cheese market.

After Britain's exit from the European Union, a temporary agreement kept tariff-free British cheese on Canadian shelves for three years. This more lenient system ended at the end of last year.

Negotiators have been working to reach a long-term bilateral trade agreement to replace the liberalized trade the United Kingdom enjoyed under the terms of the Comprehensive Economic and Trade Agreement between Canada and the European Union.

As in the aftermath of renegotiating the previous North American Free Trade Agreement, which saw changes in the sectors managing supply, Prime Minister Justin Trudeau promised dairy farmers not to offer more slices of the Canadian domestic market to exporters in future negotiations.

Dairy farmers in Canada have consistently said that expanding access to the Canadian dairy sector should remain off the table in trade talks.