New Zealand would be vitally affected if Britain gained entry to the EEC. Though aimed at freeing trade barriers between member countries, the EEC policy was to have a managed market for agricultural products, with a rigid definition of the terms of entry of produce from other countries. Unrestricted duty-free entry, which New Zealand enjoyed for most of her food products in Britain, seemed incompatible with this type of market.
Read the full government statement on what an enlarged EEC meant for New Zealand.
The pdf is available to download here.
The time had come when Britain had to make the choice on whether or not to join the European Community. It was an historic decision. This document records the results of the negotiations between Britain and the Six,and sets out the difficulties as well as the opportunities of joining.
To read the document in full the pdf is available here.
There was some opposition to membership and a few disparate groups produced critical publications. '12 Reasons why Britain should not join the European Common Market' is typical.
It is amazingly accurate in its predictions. To see this leaflet in full the pdf is available here. 
A leaflet produced by the Sunday Express and the Anti Common Market League entitled 'Don't be Fooled' engendered little countrywide support although it,also,was succinct and accurate.
To see this leaflet in full the pdf is available here. 
In 1971, during the final stages of the negotiations for Britain's entry into what was then termed the "Common Market", the anti-marketeers had made some impact with the claim that membership would involve an unacceptable loss of sovereignty. This document is massively important for many reasons, not least because it demonstrates that the Foreign & Commonwealth Office had a very clear idea of the repercussions of joining the "Community", as it put it. It knew that it would involve a major loss of sovereignty and, in due course, an end to parliamentary democracy. This document was suppressed for thirty years!
If you wish to read it now the pdf is available here. 
What would be the effect on Britain if we gave up membership of the Common Market? In the Government's view, the effect could only be damaging. Inevitably, there would be a period of uncertainty.
Read the leaflet in full why you should vote NO,the pdf is available here. 
'I believe that both the security and the prosperity of the country depend upon a Yes vote. Not to have gone into Europe would have been a misfortune. But to come out would be an altogether greater scale of self-inflicted injury. It would be catastrophic' Roy Jenkins 26th March, 1975.
Read the leaflet in full why you should vote YES,the pdf is available here. 
Britain's New Deal in Europe, the document issued by the then Labour Government prior to Britain's entry into the Common Market. It says:"Your right to choose ...' The Labour Party manifesto in the election made it clear that Labour rejected the terms under which Britain's entry into the Common Market had been negotiated, and promised that, if returned to power, they would set out to get better terms.The British people were promised the right to decide through the ballot box whether or not we should stay in the Common Market on the new terms".
Read this document in full the pdf is available here. 