The Deputy First Minister has insisted that SNP ministers “aim” to tell the truth after Health Secretary Michael Matheson admitted lying to the public over £11,000 of charges run-up on his Holyrood iPad.

It comes as the Scottish Parliament Corporate Body (SPCB) confirmed it will “undertake an investigation in line with its duties under the MSP code of conduct” into Mr Matheson’s expenses claim at the centre of the row.

The SPCB will investigate Mr Matheson's initial claim of around £8,000 of the £11,000 bill which he put through his parliamentary office expenses before he agreed to foot the entire bill after an initial backlash.

The probe will determine whether his expenses claim was "proper" and "met the requirements" of the Holyrood expenses scheme for MSPs and "whether resources were used for parliamentary purposes in accordance with all SPCB policies".

Mr Matheson said he will “fully co-operate” with the probe.

Subject to the internal investigation by Holyrood officials, the Health Secretary could be referred to the Parliament's standards committee. 

Mr Matheson revealed last Thursday that his teenage sons had used the device as a hotspot so they could watch football while on a family holiday to Morocco.

The bill for the data roaming charges was initially paid by the public purse, but Mr Matheson paid the money back to the Scottish Parliament after learning what happened when the row first erupted two weeks ago.

But he failed to publicly mention his sons’ involvement until last Thursday – initially blaming an outdated Sim card in the device for the high costs, and insisting he had only used the iPad for parliamentary work.

Read more: Matheson accused of 'ruse' through 'bogus' referral to Holyrood body

Mr Matheson said he had found out about the use of his iPad to stream football the previous Thursday, but four days later, told journalists there has been no personal use.

This has led to questions being asked about whether Mr Matheson misled both journalists and the public over the matter – although he stressed he had been seeking to protect his children by not mentioning their role.

Pressed on whether ministers “always tell Parliament and the public the truth”, Ms Robison told BBC Radio Scotland’s Good Morning Scotland programme: “I aim, and the Scottish Government aims, to do that.”

She added: “Michael Matheson made clear in his statement that he was trying to protect his family from being part of the associated political and media scrutiny.”

Asked if that means it is acceptable for ministers to lie to protect their families, Ms Robison insisted: “No, I didn’t say that.

Read more:  Analysis: Michael Matheson: Why iPad bill makes his position untenable

“What I am saying is Michael Matheson set out the reasons that he was trying to protect his family, he set all that out to Parliament.

“He has said he will co-operate with any inquiry that is established.”

In his statement last week, Mr Matheson said he would refer himself to the Scottish Parliamentary Corporate Body (SPCB) for it to investigate the matter.

A Holyrood spokesperson confirmed afterwards there is “no mechanism for the member to self-refer in this way”.

The SPCB is due to discuss the issue when it meets on Thursday.

Read more: Michael Matheson insists he did not lie despite not telling truth

During FMQs, Humza Yousaf accepted Mr Matheson had “absolutely” made mistakes in his handling of the matter.

But the First Minister went on to accuse the Scottish Conservatives of “hypocrisy” in calling for Mr Matheson to be sacked.

Tory leader Douglas Ross used the weekly Holyrood clash to accuse Mr Matheson of trying “to dupe the taxpayer out of £11,000”, but Mr Yousaf insisted it was an “honest mistake” though said it is “right” the SPCB should “get on with the job”.

Mr Ross pressed Mr Yousaf on whether Mr Matheson had been “telling the truth” when he repeatedly denied there had been any personal use of his iPad.

He added: “If Government ministers need to be honest, why is Michael Matheson still in a job?”

Mr Yousaf replied: “Michael Matheson accepts and admitted to this chamber that he made mistakes in the handling.

“He did what he did to protect his teenage boys.

“Did he make mistakes? Absolutely. Has he admitted that? Absolutely. Has he agreed to pay back the full amount? Absolutely.”

A Scottish Parliament spokesperson said: "The SPCB met this morning to consider its next steps with regard to Michael Matheson’s statement to Parliament last week.

“While, as previously made clear, there is no mechanism for members to self-refer to the SPCB, the corporate body has a vital interest in the integrity of the members’ expenses scheme, the principle that SPCB funded resources are used for parliamentary purposes and that there is public confidence in these matters.

“The corporate body will therefore undertake an investigation in line with its duties under the MSP code of conduct.

“The investigation will consider whether the claims for £11,000 of public money, incurred through data roaming charges, were proper and met the requirements of the Scheme and whether resources were used for parliamentary purposes in accordance with all SPCB policies.

“The SPCB will seek to conclude its investigation promptly and its findings in fact, will be published.  Depending on those findings, there may be a number of options open to the SPCB, as set out in section nine of the code of conduct, including referral to the SPPA Committee."