Holyrood has struggled to hold the Government to account, a former presiding officer has said.

Sir George Reid said more scrutiny is needed to separate the legislature and executive.

He chaired a committee of the Royal Society of Edinburgh (RSE) giving evidence to Holyrood's Commission on Reform.

The committee was set up to give the Scottish Parliament ''an MOT'' and will look at issues including the processing of legislation and the committee system.

RSE said in its submission to the committee the increase in powers to the Scottish Parliament "has put a strain on its ability to fulfil key functions" and dealing with this in future may require rethinking the number of MSPs and the length of the parliamentary week.

The society said MSPs are "too skewed" to party responsibilities rather than parliamentary work and said closed party lists in elections worsen this.

MSPs could free up time for parliamentary scrutiny by delegating constituency casework and local surgeries to "trusted staff".

The submission said the role of independent committees is key to effective scrutiny of government and recommended this is enhanced, suggesting elected convenerships to increase independence, and giving a salary increase and additional staff to conveners to make the positions more attractive.

Sir George said: "To date, the Parliament has struggled to hold the Government to account.

"The Presiding Officer asks what can be done to differentiate the legislature from the executive. The answer is more informed and determined scrutiny.

"MSPs have a bigger role than simply cheering on their own side to the next election.

"Given all the uncertainties of Brexit, they have to engage in deeper and longer term policy analysis if - in Donald Dewar's words - we Scots are to say who we are and how we carry ourselves in today's world."