In a letter to the Financial Times, Sir Ronald Grierson, Former Director-General, EU Commission (1971-73), wrote:

“In all the sound and fury over whether we should stay in the European Union or get out, one simple solution appears to be overlooked: a way exists for us almost to have it both ways, to retain most of the economic benefits of membership without suffering the massive surrender of sovereignty it entails.

This seemingly magic solution is none other than the European Economic Area, an agreement that grew out of the European Free Trade Area of which the UK was a founding member before signing the Rome treaty in 1972.” Please read the letter here.