EXAMINERS' heads are on the block after a mistake in a Scottish history exam.

The Scottish Qualifications Authority (SQA) got the wrong date for Mary Queen of Scots’ execution in the National 5 exam.

The paper wrongly stated that Mary Stuart died in 1567 - 20 years earlier than her actual death.

Sir Tom Devine, emeritus professor of history at Edinburgh University, said the mistake was "unacceptable”.

He added: "It is slightly cheering to know that the examination board don’t know everything about Mary, because I thought that everyone knew the whole lot, right down to the undergarments she wore at her execution.”

The SQA promised that no candidate would be disadvantaged as a result of the blunder.

A spokesman said: "We are aware of a typographical error concerning the date of Mary Queen of Scots’ execution.

"This will not have affected the understanding or interpretation of the question. We will consider this when the paper is being marked to ensure no candidate is disadvantaged."

The error was printed in an introduction to source material for the question from the diary of a lady in waiting who accompanied Mary during her imprisonment in England.

Pupils were asked to evaluate the usefulness of the source "as evidence of the execution of Mary Queen of Scots in 1567".

The diary stated that Mary’s knelt before the block with “great courage” and showed no signs of faltering.

It added: "The executioner, or rather minister of Satan, strove to kill not only her body, but soul, because he kept interrupting her prayers.

“When she eventually finished praying she laid her head on the block. The executioner struck her a great blow on the neck, which was not, however, entirely severed.”