Senior MSPs said they felt that the current system leaves them “helpless” to act against colleagues guilty of wrongdoing.

It follows the case this week of Mark McDonald – as well as that of Bill Walker, who in 2012 was accused of domestic violence – which saw politicians remain in their seats in the face of calls to stand down.

Liberal Democrat leader Willie Rennie has now called for a summit of all party leaders at Holyrood to look into the prospect of the “recall” of MSPs in order to “protect the reputation” of the Scottish Parliament.

First Minister Nicola Sturgeon has urged Mark McDonald to step down as an MSP, after a damning party report found he pestered women with unwanted attention. Picture: Jeff J Mitchell/Getty Images

The issue came under the spotlight at Holyrood’s standards committee yesterday, which took evidence from party business managers after a recent survey of parliamentary staff revealed a fifth had suffered some form of sexual harassment.

At present MSPs only lose their seats if they are jailed for more than a year. Mr Walker resigned his seat under pressure from fellow MSPs, and served half of a 12-month prison sentence for domestic violence offences.

The SNP’s Tom Arthur asked how some form of “ultimate sanction” could be applied to MSPs guilty of serious misconduct which does not lead to a lengthy jail sentence.

Mr Rennie said he had been a “long-term advocate” of a system of recall. But he said: “You need to be careful that it’s not being used for political motives, that it’s based on disciplinary issues.”

He said MSPs should look at the Westminster system, which allows MPs to be recalled if they have received a prison sentence of less than 12 months, if they have had a suspension from the standards committee or if they have submitted fraudulent expenses.

“I think that would in some way help us to police ourselves in certain circumstances,” Mr Rennie said. “We’ve had a number of individual cases … going back a number of years as well and we’ve felt helpless to do anything about it.”

He has now invited party leaders to a discussion on how to use the powers of the Scottish Parliament to protect its reputation and integrity in light of recent events.

In the letter he called for all parties to look at the range of “sanctions and mechanisms” available in future in the event MSPs are found to have done something wrong. The Scottish Parliament has the power to introduce a system of recall similar to that in England.

First Minister Nicola Sturgeon has previously backed proposals that would allow people effectively to “sack” their elected representative.

In the run-up to the 2014 independence referendum, she claimed the right to recall could be enshrined in a written constitution for Scotland.

Her predecessor, Alex Salmond, also lobbied for the devolution of recall powers when Walker was found guilty. These now rest at Holyrood.

The recall system at Westminster means MPs can face losing their seat and a by-election if they are jailed for less than a year, if they are suspended by Parliamentary authorities for more than a fortnight or if they submit fraudulent or misleading expense claims.

A jail sentence of more than a year means MPs as well as MSPs are automatically kicked out.

Greens co-leader Patrick Harvie said he would have “serious concerns” about a recall system over issues such as sexual harassment as it would turn a serious disciplinary matter into a “public campaign”. Instead he backed a “neutral system”.

Mr Harvie said: “For the most serious issues where you would want a serious disciplinary option to be available, it seems to me that needs to be tapping into an independent and official process for disciplining MSPs, not necessarily a party, because that may not have the option of taking that disciplinary measure.

“I think there is a far stronger case for reviewing the disqualification criteria which currently exists and ensuring that, like in any other workplace, where certain standards of behaviour have been failed, there is a disciplinary process which can result in somebody being dismissed on grounds of gross misconduct.”

Labour’s Rhoda Grant also backed calls for change.

She said: “There has to be a process that deals with someone whose behaviour has fallen short and it shouldn’t be a political process, it shouldn’t be a public process.

“We have standards commissioners and the like that look at people’s behaviour so we should be looking at that system to see, if there are ways, when a case it proven against a person, when their behaviour has fallen way short of what we expect from an elected representative, that there are steps that can be taken.”

SNP business manager Bill Kidd said the issue of future action against MSPs could be taken forward through Holyrood’s corporate body.

The Glasgow MSP suggested Holyrood could borrow from other parliaments and come up with “new ideas, as to how we handle the future prospects of those who have either committed gross misconduct or criminal acts”.

Mr McDonald announced he was quitting the SNP this week after a damning party report which found he pestered women with unwanted attention, sent inappropriate text messages and abused his position of power.

But he has said he will remain as the Aberdeen Donside MSP, sitting as an Independent. Ms Sturgeon and opposition politicians have called on him to resign, insisting that if his conduct was bad enough for him to quit the SNP, it should also be bad enough to quit as an MSP.

Holyrood authorities have been forced to find a new room for him in the MSPs’ office block after SNP bosses called for him to be removed from his base on the Nationalist floors.

Moves to change rules to remove misconduct MSPs