Prime Minister Edward Heath’s officials estimated that up to half the fishermen in Scottish waters - then 4,000 men - could lose their jobs, but the decision was taken to go ahead with plans to sign up because it was believed that the benefits to English and Welsh fishermen would outweigh the disadvantages in Scotland.
Three decades on, with the same policy now threatening the very survival of the Scottish whitefish fleet, the new revelations are certain to fan the flames of deepening unrest in Scotland’s coastal communities.
In a memo dated 11 December 1970, on the negotiations to sign up to the CFP, the department of Agriculture and Fisheries for Scotland conceded that the policy would lead to a "weaker and less efficient national fleet".
A DAFS briefing note warned: "In short, at present it is much easier to see the drawbacks for our fishermen likely to be involved in the Common Fisheries Policy than to be at all positive that there will be benefits to offset, let alone outweigh them."
Another DAFS paper in July 1970 warned that the small boat section of the Scottish industry would be damaged and the benefits might not outweigh the disadvantages.
It said the small boats were more likely to be affected because they were "less enterprising and less mobile".
Alex Smith, the president of the Scottish Fishermen's Federation, said that the release of the secret papers had only served to confirm what Scottish fishermen had always suspected - the Scottish fleet was expendable.
He said: "I have never doubted that that was what happened. No-one seemed to care about the Scottish fishing industry and at one time there wasn’t even going to be even a three mile limit for Scottish boats.
"I was a skipper in Arbroath at the time we joined the Common Market. There was no such thing as a fishermen’s federation in those days and it was fishermen in Arbroath who began opposing the plan.
"I was on our committee and we organised a big meeting, attended by 200 fishermen from the north and west and all over. And it was out of that we managed to negotiate the ten year 12-mile limit."
But he added: "The reality is that it is done and dusted and although it won’t look good for the politicians and civil servants who were involved at the time, the question is what we can do about it now.
"If it jolts our present day politicians into giving some sympathy and support to the industry because they have a conscience about what happened in the past then that might be helpful.
"But my main worry is the power that the European Fisheries Commission now has to imperil this industry under the CFP."
The truth about the sell-out of Scotland’s fishermen is one of a number of revelations hidden in government paperwork from 1972 which is released for the first time including an insight into Labour and Conservative thinking on devolution.
A letter from Harold Wilson to the General Assembly of the Church of Scotland observes that, whilst he was not against change, he believed Scotland benefited from the status quo.
But the Scottish Economic Planning Council, set up by the Scottish Office, comes out strongly against devolution, claiming that it would create an anarchic battle with the English regions for funding and that if there was any need for improvement it would already have been tackled.
Among the other revelations is a government plan to close all the Upper Clyde shipyards in 1972 and move the entire workforce to a new purpose-built site in Ardrossan in an attempt to revitalise the crisis-hit industry.
With yards running out of work and serious labour disputes prompting police to warn of the risk of "almost uncontrollable conflict", the plan was to rehouse the Glasgow workforce - possibly in the new town of Irvine or in Greenock - and provide them with free transport to the new yard.
The Conservative government believed that the cost of the unorthodox plan would still be lower than the 32 million which it would cost to set up the proposed new Govan Shipbuilding company. But with order books empty, time ran out and the plan had to be abandoned.
‘Catholic-free’ Ulster policy
THE Heath government had devised a secret policy of ethnic cleansing involving the forcible expulsion of hundreds of thousands of Catholics from Ulster to create a Protestant-only province.
Edward Heath’s officials drew up secret plans that would see 500,000 people moved from their homes and the redrawing of the border, according to documents just released.
The proposals were aimed at creating an "avowedly sectarian statelet".