THE so-called McCrone Report was a document prepared by Dr Gavin McCrone, then a senior civil servant in the Scottish Office and chief economic adviser to the Secretary of State for Scotland.

It examined the prospects for the Scottish economy as a result of the discovery of oil in the North Sea in 1970 and how that might influence the growth of Scottish nationalism and the politics of independence.

The report was classified as “secret” by the Scottish Office and UK Government of the time, and only came to public attention in 2005 when new freedom of information legislation came into effect.

It is hardly surprising that the document remained confidential for so long. The report argued that the oil discoveries in the North Sea had transformed the case for Scottish independence and demolished the old belief that Scotland did not possess the economic resources to go it alone.

Read more from our McCrone 50th Anniversary special edition here:

It was political dynamite as McCrone concluded that “for the first time since the Act of Union was passed, it can now be credibly argued that Scotland’s economic advantage lies in its repeal”.

The author had a high academic reputation and knew more about the Scottish economy than any other government official at the time. McCrone’s remarkable assessment could therefore not easily be discounted.

The decade of the 1970s was one of successive balance of payments crises, currency devaluation and widespread strikes which culminated in the Winter of Discontent.

For British governments, the oil therefore came as godsend, a panacea for all these economic ills.

Any leak or publicity for the findings of the report could threaten that expectation and only give enormous political comfort to the nationalists, who were riding high, having won one-third of Scottish seats in the second General Election of 1974.

The stakes could not have been higher.