Britain historically favoured trade with member countries of the British Commonwealth, such as Canada. But under the terms for Britain joining the EU, this was seen as a form of favouritism by Britain. As a condition of entry to the EU such trade would have to stop. Free trade was only to be between EU countries, and tariff barriers might even be raised against countries who were not members of the EU. This was like a test by the EU to determine Britain's sincerity in applying to join. Tariffs would be totally unfair on the Commonwealth, but Britain went ahead and joined the EU anyway.