Politics in Scotland has become "increasingly tribal" in recent years, Holyrood's presiding officer has said.

Ken Macintosh, who has been in the role since May, believes the problem has led to the job of being an MSP becoming "more challenging".

To tackle the issue he established an independent commission to review Holyrood's parliamentary functions.

He has appointed the outgoing electoral commissioner for Scotland, John McCormick, to lead the review.

It is expected McCormick will submit his review to Holyrood in June 2017.

Macintosh said: "In 1999, the Scottish Parliament was hailed as groundbreaking, bringing a new, inclusive style of politics to Scotland.

"However, over the last decade or more, we have seen Scottish politics become increasingly tribal and divisive.

"This has, among other things, made it challenging for MSPs to find the space to develop in their distinct role as parliamentarians.

"I want the commission's work, therefore, to help bring the Parliament back to its roots, ensuring Holyrood is open, transparent, truly participative and fit for the significant challenges which lie ahead."

Macintosh believes the upcoming 21st anniversary of the parliament's establishment is a good time to review what can be done to tackle the issue.

He said: "During this session the Scottish Parliament will turn 21, and in its lifetime we will have seen coalition, majority and minority government, further devolution of powers and a digital revolution.

"The time is therefore right for us to reflect on our experience and take a serious look at how the parliament should evolve to ensure it best meets the needs of the Scottish people.

"I believe an independent, external commission is the best vehicle for achieving that."

He added: "The parliament's systems are not broken but they are in need of an MOT. This is not about revisiting the work of the consultative steering group, our founding principles are as relevant today as they were in 1999.

"Instead I am asking the commission to take a fresh look at how we conduct our business and to deliver practical recommendations for change".

The presiding officer said he has the support of the parliament's five party leaders.