When the negotiations that were eventually to result in the Rome Treaties began in early summer of 1955, there were not six countries represented but seven. Also present was a delegation from the United Kingdom. Partly because of an antipathy towards federalist ventures and partly refl ecting the lack of orientation of the UK's trade towards Europe, in November 1955, the British cabinet decided against joining the Common Market. Since, at the time, the Foreign Office was cultivating the view that the most likely outcome of the talks was failure, the cabinet ignored the warning that should the Six succeed, Britain's position outside the group could be painful. Therefore, when the Common Market negotiations singularly failed to collapse, the need for an alternative strategy began to penetrate some sections of the government.

The driving force behind the new approach was Peter Thorneycroft, president of the Board of Trade. He was firmly supported by Harold Macmillan, who had recently been transferred from the Foreign Office to the Treasury. Their concern was to channel the effort of the Six in directions that could contain British interests. As Thorneycroft warned the prime minister in January 1956: ‘No fine words would disguise the reality of a discriminatory bloc, in the heart of industrial Europe, promoting its own internal trade at the expense of trade with other countries in the free world.’

A restricted meeting of ministers decided in May 1956 to focus the study for an alternative policy on the possibility of creating a partial free trade area in Europe. Properly conceived, it seemed big enough to be attractive to Europeans, whilst leaving open the possibility for keeping privileged access to Commonwealth imports. At the end of July the plan was ready for consideration by cabinet. It would apply to all OEEC countries, but only to industrial products. By excluding agriculture, policy-makers hoped to be able to keep preferences on most goods bought from the Commonwealth (and thus the reciprocal preferences enjoyed by UK manufacturing exports) and to keep tariff protection for British horticulture. Largely because European trade gains no longer had to be set against Commonwealth losses, the balance of official reaction was more positive than it had been on the Messina initiative.