Michael Matheson told Holyrood’s Presiding Officer that he did not know why his data roaming bill was so high after he knew that his boys were to blame, according to reports.

The SNP MSP - who quit as health secretary last Thursday - met with Alison Johnstone after he was told by his wife that the teenagers had used his parliamentary iPad as a wifi hotspot during a family holiday in Morocco.

The Sunday Mail reports that despite this, he told the PO he had no idea why the charges were so high.

Scottish Conservative leader Douglas Ross said Mr Matheson's position as an MSP was now "untenable." 

He said the ex-minster had "disgraced his office and shown contempt for the parliament."

READ MORE: Michael Matheson's departure is just the start of problems for Yousaf

It’s understood Mr Matheson met with Ms Johnstone after he learned about his children’s use of his parliamentary iPad on 9 November and before his personal statement to the Parliament on 16 November.

The MSP for Falkirk West has already admitted lying to the press about the charges during this week.

On 13 November, when asked directly if there was "any personal use" of the device during the family holiday, he told reporters: "No”.

When asked if anyone else could have used the device, he, again, said, "No".

He later said this was because he wanted to “protect my children from getting involved in something that had significant parliamentary, political, and media interest."

The ex-minister looks set to be referred to either Holyrood’s standards, procedures and public appointments or the Ethical Standards Commissioner and could be at risk of being suspended as an MSP.

READ MORE: Michael Matheson quits as health secretary

A source told the paper: “There is a paper trail which doesn’t show him in a good light whatsoever. He has lied flat out to the presiding officer after he found out his kids had used the iPad. He was asked about it and he didn’t mention his kids using it whatsoever. It was an extensive meeting”.

They said a report, by the Scottish Parliament Corporate Body (SPCB) into Mr Matheson's iPad use and expenses claim, contained “exchanges where he was resisting telling the truth about the data usage and the reason for the bill”.

When details of the eye-watering charges first emerged on November 8, the MSP repeatedly denied that he had used his work iPad for personal reasons, insisting the bill was “a legitimate parliamentary expense”.

The Sunday Mail also reports that Mr Matheson’s lawyer had been passed the findings of the SPCB probe the day before he quit.

That's despite his resignation letter saying he had not seen a copy of the investigation's findings. It only said that it was in the "best interest of myself and the Government for me to now step down to ensure this does not become a distraction to taking forward the Government's agenda."

A source close to Mr Matheson said: “He was right in saying he had not received the report because he hadn’t, but of course he knew what was in it otherwise he wouldn’t have resigned. I think he should have just admitted that he knew the report wasn’t going to look good for him.

"Instead he’s done another bizarre thing by saying he hadn’t received it but he was going to step down anyway. His behaviour throughout this whole scandal has been very unlike the Michael we’re used to and it’s hard to understand how and why he managed to mess this up so badly.”

READ MORE: Michael Matheson 'misled' Presiding Officer over £11k data bill

Meanwhile, according to correspondence obtained by the Scottish Sun on Sunday, aides to First Minister Humza Yousaf initially wanted to blame Mr Matheson's charges on Brexit

A Scottish Government special adviser wrote: “Presumably Mr Matheson’s charges relate to foreign travel when [cabinet secretary for net zero, energy and transport].

“Can we make sure lines cover Brexit being reason any of us have roaming charges in Europe?”

 Mr Yousaf's handling of the affair has also come in for some criticism.

One ex-cabinet minster told the Sunday Times: "The handling of the whole situation is a textbook example of how to do all the wrong things. You have to give the appearance of being in control and Humza simply hasn’t done that.

“Three months ago, there was a case for not giving in immediately to the hyenas. But at that point he had to find out the truth, then make a judgment.

“If he’d got to the bottom of it in November, after a couple of weeks the FM could have said: ‘Look Michael, I don’t want to lose someone of your competence, but we have to recognise you’ve made a mistake. Say you’re sorry, step down, and in a year or so, I’ll bring you back’.

“Instead he waited until the eve of publication for the resignation.”

Responding to the latest allegations, Douglas Ross said: “We already knew that Michael Matheson lied to the public and the press, which is why he should have been sacked as health secretary months ago – yet Humza Yousaf was too weak to do the right thing.  

“But if the report shows he lied to the Presiding Officer about his iPad use, then his position as an MSP is untenable too.

“Remember, it was Michael Matheson and the SNP who initiated this investigation and called for due process – supposedly to get to the bottom of what happened – but as his story changed it seems he repeatedly lied to try to cover his tracks.

"He has disgraced his office and shown contempt for the parliament and, therefore, is unfit to be a member of it.

“This whole affair demonstrates Humza Yousaf’s appalling judgment and the sense of entitlement of an SNP Government that has been in power for far too long."

Labour deputy leader Jackie Baillie MSP said: “It’s very clear that Michael Matheson lied to the parliamentary authorities and made an entirely inappropriate claim for expenses.

“This also demonstrates the poor judgement of Humza Yousaf, putting the interest of the SNP before the interests of the NHS. Michael Matheson was distracted from doing his job and should have been sacked months ago.”

Mr Matheson - who is in line for a nearly £13,000 severance payout - has been approached for comment.