Michael Matheson's fate could be determined tomorrow by his former colleague Ash Regan, who now sits as an Alba MSP.

The former health secretary is face a knife edge vote over whether he should be suspended from Holyrood for 27 days and lose 54 days salary.

A cross party committee of MSPs last week recommended the sanctions against the former health secretary over a near-£11,000 data roaming charge bill on his parliamentary iPad whieh he racked up while on a Christmas family holiday in Morocco.

Parliament is due to vote on whether to approve the recommendations tomorrow afternoon, but John Swinney told Holyrood last Thursday he would not be supporting the punishment, accusing the committee of being prejudiced because of comments previously made by one of its members Annie Wells about Mr Matheson's iPad bill.

Holyrood has 63 SNP MSPs and 65 opposition MSPs meaning the vote will be extremely close. 

READ MORE: Matheson to face knife edge vote on Holyrood suspension

Conservative, Labour, Lib Dems and Scottish Greens are expected to back the motion calling for the sanctions to be imposed on Mr Matheson, while SNP MSPs are expected to oppose it.

If all those MSPs vote according to party lines, the vote would stand at 64 for the motion 63 against.

However, it is not known yet how Ms Regan, a former SNP leadership candidate who defected to Alex Salmond's Alba Party will vote.

Ms Regan, pictured below, has not responded to The Herald's request asking her how she will vote.

The Herald:

If she sides with the opposition parties, the vote would be 65 to 63 if all MSPs vote and Mr Matheson's suspension would come into force from Thursday. But if Ms Regan sided with the SNP the result of the vote would be a 64 64 tie. 

The tie would mean that the Presiding Officer Alison Johnstone would step into give her casting vote.

The Presiding Officer Alison Johnstone does not normally vote but does so in the event of a tie. She votes according to a protocol of supporting the status quo. It is unclear what the status quo means in the situation, whether to support the committee report and sanction Mr Matheson or not.

READ MORE: 'Swinney ill-advised to defend Matheson from MSPs sanctions'

Asked how the Presiding Officer would vote in the event of a tie tomorrow, a Holyrood spokeswoman said: "As is usual when the Parliament has not been able to reach a decision, the Presiding Officer Alison Johnstone is obliged to exercise a casting vote. The Presiding Officer will not make the decision for the Parliament. The established convention is to vote in favour of the status quo, because the chair is required to act impartially."

The statement is perhaps open to interpretation but seems to suggest the Presiding Officer would not vote to sanction Mr Matheson as his punishment is a departure from the status quo.

The debate and vote on the standards committee's report will take place in Holyrood from 2.50pm to 3.20pm tomorrow.

The motion tabled by Martin Whitfield, the Labour MSP who is convener of the standards' committee, states: "That the Parliament notes the Standards, Procedures and Public Appointments Committee's 1st Report, 2024 (Session 6), Complaint against Michael Matheson MSP (SP Paper 597), and agrees to impose the sanctions recommended in the report that the Parliament excludes Michael Matheson MSP from proceedings of the Parliament for a period of 27 sitting days and withdraws his salary for a period of 54 calendar days to take effect from the day after this motion is agreed."

A separate Conservative led debate calling for Mr Matheson to resign as a MSP will be held immediately afterwards. The Scottish Greens will not support the Tory motion meaning that it is highly unlikely the motion calling from him to step down as an MSP will pass.

The development comes as James Mitchell, professor or public policy at Edinburgh University, said he did not think it likely the First Minister should have defended Mr Matheson from the committee's recommendations and doubted if he would have pursued such a course of action if key aide Kevin Pringle still being advising him.

Mr Pringle, a long serving SNP strategist, who advised Alex Salmond, Nicola Sturgeon and Humza Yousaf when they were first ministers, was not rehired by Mr Swinney.

Professor Mitchell said the ongoing row over Mr Matheson's actions was overshadowing the SNP's general election campaign and along with other troubles gave voters the impression of a party that was "entitled".

The Falkirk West MSP, a close ally of Mr Swinney, claimed an £11,000 roaming charges incurred on his parliamentary iPad from the Holyrood expense account, saying it was for legitimate parliamentary business, before it emerged that his sons had run up the bill watching football online on a Moroccan holiday. He has paid the money back to the parliament.

Last week, Holyrood's standards committee investigating his conduct handed Mr Matheson a 27-day suspension from the Scottish Parliament alongside a 54-day pay cut, roughly equivalent to the size of the bill.

“John Swinney’s defence of Michael Matheson was ill-advised.  It seems unlikely that someone like Kevin Pringle, a more experienced and informed adviser, would have proposed this course of action," Professor Mitchell told The Herald.

"The tendency of the SNP to refuse to own its failures and misdemeanours but to try and turn criticisms on its critics is especially cynical but will do the SNP no good.  

"It may now be too late for a fulsome and unqualified apology and acceptance of the committee’s recommendation as was required and, as SNP canvassers will no doubt become well aware over the coming weeks, expected by the public.  Many people are struggling to pay bills and will be appalled by a First Minister trying to deflect criticism in defence of a party colleague."

He added: "It would have helped had Annie Wells recused herself though this is not the main issue but is a matter that may need attention at some point.  A replacement for Ms Wells would in all likelihood have made no difference.  

"The question that may need to be addressed in light of this episode is whether an alternative, more independent body ought to make such decisions.  

"Having MSPs sit in judgment on each other should not be a problem but if party politics intrudes then party politicians may need to be removed from decision making.  This would be a great pity but may be necessary.   However, it would be wrong to make any major changes based on this one example."  

Asked about the standards' committee's recommended sanctions during First Minister's Questions last week, Mr Swinney pointed to remarks made by the Tory MSP Ms Wells when she said the "desperate efforts" by Mr Matheson to justify his expenses claim had been "riddled with lies, cover-ups and the need for us all to suspend our disbelief."

Speaking to journalists today Mr Swinney during a visit to the Scottish Poetry Library in Edinburgh, he said the row over Mr Matheson's sanctions had not overshadowed the first week of the SNP’s General Election campaign.

“I’ve been out and about, talking to lots and lots of people as part of my travels around the country and people are talking to me about a whole range of different issues which matter to them,” he said.

“Those matters are about the effect of austerity on our public services, businesses that are telling me that Brexit is causing them ongoing difficulties and then I can’t speak to a household without them expressing concern about the cost of living.

“So, those issues are the issues that I’m engaging on with members of the public.”

Scottish Conservative Chairman Craig Hoy: "John Swinney is continuing to defend the indefensible by backing his friend and SNP colleague Michael Matheson."