A prominent educationalist has described the "mountains" of guidance issued to teachers as "self-evident lunacy".

Keir Bloomer told Holyrood's Education Committee that the overload of "nearly incomprehensible" information stands in the way of "de-cluttering" the school curriculum.

Education secretary John Swinney has already pledged to cut teachers' workload, following complaints that the profession has been overburdened by bureaucracy as Curriculum for Excellence has been rolled out.

Plans include scrapping some unit assessments which are marked by teachers before pupils sit their exams, and "empowering" teachers as part of a review of how schools are run.

Mr Bloomer, who is convener of the Royal Society of Edinburgh's education committee, said he is pleased Mr Swinney "is determined to do something about it".

He added: "We have allowed mountains of guidance, much of it very badly written, nearly incomprehensible, to accumulate over the years, and that now stands in the way of the de-cluttering of the curriculum."

While some political mistakes have been made, "most mistakes have actually been made by the leadership of the profession", Mr Bloomer added.

"The quality of advice that governments have received has not been strong and there has been a lack of strategic overview of the process as a whole.

"The overall consequence has been to obscure rather than illuminate."

He continued: "Either you trust the teaching profession or you don't. The whole philosophy of Curriculum for Excellence is that you trust the profession. That you set a sense of direction... you supplement that with a limited amount of strategic advice and you trust the profession to implement it."

Mr Bloomer - one of the architects of Curriculum for Excellence - also highlighted a lack of evaluation of it.

He said: "We do not know what progress has been made because no serious attempt has been made to evaluate it.

"This is the most significant development that has taken place in Scottish education since the war and no evaluation system was set up at the outset.

"Successive governments have made claims of success in relation to Curriculum for Excellence and to be honest with you, they are based on no evidence whatsoever."