IT is one of Scotland's most historic plays, a four-hundred-year old morality tale that caused a cultural sensation when it was re-staged at the Edinburgh International Festival 70 years ago.

The Satire of the Three Estates by Sir David Lyndsay, first shown to Scots royalty in 1540, was brought back to life in one of the earliest Edinburgh Festivals and has remained a touchstone for Scottish drama since.

However, a new celebration of that production has caused unease within the family of one of its key architects.

The "legendary" 1948 production was directed by Tyrone Guthrie, and was performed from an abridged, edited and adapted Scots text by the writer Robert Kemp - an event marked at this year's Festival to signal its 70th anniversary.

The family of Kemp have now expressed their irritation and disquiet that their father's crucial work in refining and editing the vast play has not been credited by the 2018 festival.

David Kemp, the son of Robert Kemp, and the brother of the late editor of The Herald, Arnold Kemp, is dismayed that his father's crucial work has been overlooked by the EIF.

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Today, the director Joe Douglas and the dramaturg Ian Brown will lead a presentation of a new version of the play, and a discussion on how it might be presented to a modern audience.

Mr Kemp, however, is anxious that his father's contribution is not forgotten.

In the this year's festival programme, Guthrie, the director, is mentioned, but the writer and adaptor of the 1948 version, Mr Kemp, who died in 1967, is not.

David Kemp, a retired TV producer, said: "I think it is a real insult to him that he should be ignored in this way.

"There is no mention of him at all.

"I do not want to be strident about it, but I would like to say that the Kemp family are upset by this, the lack of mention of his work."

He added: "I am surprised the Festival Society did not twig to this, and say: we are dealing with our own history here, let's get it right.

"He wrote other plays at the festival: he was a central and seminal figure."

Jackie Kemp, a business content creator and grand-daughter of Robert, added: "Robert Kemp’s reworking of the Three Estates was a huge achievement.

"Robert was a gifted playwright and storyteller who spoke and wrote in Scots - but he was also a scholar of the language, with a deep knowledge of its literature and history.

"He is part of a tradition and would be happy to see others reworking the original text - but I think he deserves to be remembered and recognised for his contribution."

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Mr Kemp noted that he was still waiting for an apology for the oversight.

A statement from the EIF said: "The rehearsed reading presented by the International Festival, Lyceum Theatre and National Theatre of Scotland, uses extracts adapted from the original 16th century play by Sir David Lindsay, rather than the 1948 work adapted by Robert Kemp and directed by Tyrone Guthrie.

"The International Festival recognises Robert Kemp’s enormous contribution to the landmark 1948 production and the extraordinary legacy of this piece, which continues to inspire theatre makers to this day."

The play was first performed at Linlithgow Palace, probably in the Banqueting Hall in 1540, before King James V and the queen, Marie de Lorraine.

In his written introduction to The Satire of the Three Estates, Robert Kemp, writing in 1948, said he hoped his notes show how he "tackled the problem of making an old Scottish classic actable by modern actors and comprehensible to a modern audience, whilst doing the least possible violence to it."

He added: "When the Festival Committee announced that Scottish drama was to be represented by a four hundreds year old morality play, which had not held the stage in the interval and did not so much as figure in the leaving certificate examinations, even the most patriotic seemed to feel that here was boldness to the point of recklessness."

Mr Kemp's version was cut until the play last around two hours.

He said: "I had to cut where the Satire was too long and too broad."