That is total crap from the Guardian. The UK has robust trade with the United States and many other nations that are not part of European Community. The UK is a net subsidizer to the European Community and not a net beneficiary. France sure as hell will not refuse to sell their cheese (they make good cheese) wine, Puegots etc. to the UK. If France imposes great taxes on UK products the UK will do the same to France, Germany etc.
This is nothing but scare tactics by the hard left wing Guardian which is a one worlder newspaper. The original concept of the European Economic Community was brilliant. It promoted free trade and commerce among its members. It was wildly successful. It slowly morphed into "European Government," which today is called the European Union. That is why the new European Union is failing. Individual nations do not want other nations determining their individual domestic policies and laws.
I forgot to add, Norway is not a member of the European Union. They have negotiated their individual trade deals with the Union Nations. Norway is economically robust today.
The EEC was never a good idea. Even at this early stage it was a protectionist bloc that hampered our trade with the rest of the world by forcing us to erect tarriffs against countries outside the bloc. We shafted our Australian and NZ bretheren who were heavily dependent on exports of lamb, butter and other agricultural goods to the UK at this time and I’m amazed they still have such goodwill towards us after the way we stuffed them over so that we could embrace our historic enemies.