Documents dated Sept. 10, 1956, show French Prime Minister Guy Mollet made the proposal to British Prime Minister Anthony Eden during a visit to London, the BBC reported. France was having problems in Egypt, where President Gamel Abdel Nasser had nationalized the Suez Canal and was also funding separatists in French Algeria.

Eden turned down the request for a union, but while he was in Paris the following Sept. 28, Mollet then suggested France be allowed to join the British Commonwealth.

However, nothing more came of the exchanges, and no records of them appear to exist in the French archives, the report said.

Henri Soutou, professor of contemporary history at Paris's Sorbonne University was aghast when he learned of the exchange.

"Really I am stuttering because this idea is so preposterous," Soutou told the BBC.

Similarly, nationalist member of French parliament Jacques Myard said he was "astonished" by Mollet's plans.

"I had a good opinion of Mr. Mollet before. I think I am going to revise that opinion," he said.