A senior SNP minister has backed under-pressure Health Secretary Michael Matheson – insisting he should continue his key Scottish Government role “for a very long time”.

Mr Matheson faces a fight to keep his job after he lied to the public about knowing his sons had used a parliament-issued iPad to watch football and tally up almost £11,000 in data roaming charges, which were then picked up through his Holyrood expenses.

The Health Secretary finally agreed to pay the entire bill but told journalists on Monday that the iPad in question was not used in any personal capacity during a family Holiday to Morocco at the turn of the year.

In an emotional statement to Holyrood yesterday, Mr Matheson admitted he had discovered his son had used the iPad to watch football last Thursday.

Meanwhile, First Minister Humza Yousaf branded his senior minister as having “honesty and integrity” yesterday, despite knowing he had lied about what had happened.

Read more: Humza Yousaf 'lying to public' over Michael Matheson's iPad scandal

SNP Constitution Secretary Angus Robertson has backed Mr Matheson, who he has known for decades.

Mr Robertson was speaking to journalists at a media event to launch the Scottish Government’s latest papers on renewing the case for independence.

The senior minister labelled his colleague “a proper person” and “a very competent person”.

He said: “I know he's been working very hard in relation to the National Health Service and I hope he continues to do so for a long time.

The Edinburgh MSP stressed that “any fair-minded person” would but Mr Matheson’s story of events.

He added: “I want him to continue working as Scotland's Health Secretary.

"I think it's also the right thing for him to have done to have referred himself to the parliamentary authorities, who will be looking at those circumstances, and it is not for me to second guess that.”

Read more: Michael Matheson blames teenage sons for £11k data roaming bill

But opposition MSPs have called on Mr Matheson to resign.

Yesterday, the Health Secretary rejected calls to fall on his sword and denied suggestions he had offered his resignation to the First Minister.

Scottish Labour leader Anas Sarwar said he had “every sympathy” for Mr Matheson but insisted that the Health Secretary must now consider his position.

He said: “I’ve got every sympathy for a dad that struggles with teenage boys – I’ve got two teenage boys myself.

“But the issue here is the cover-up. Michael Matheson has changed his story.

“He has now admitted that he became aware on Thursday what the true situation was but continued for three or four days afterwards to tell mistruths about what actually happened and mislead both Parliament and the public.”

Mr Sarwar added: “That’s not right and it’s not appropriate. He also says he told the First Minister on Tuesday – why did the First Minister then mislead the public on Wednesday?

Read more: Scottish Parliament publishes Matheson's £11k data roaming bill

“I think there are serious questions that need answering and I absolutely think Michael Matheson should be considering his position.”

Scottish Tory leader Douglas Ross has written to the First Minister to demand an apology and explanation to the public after he said he had “full confidence” in Mr Matheson.

He said Mr Yousaf’s “integrity is on the line every bit as much as that of his friend”.

He added: “He owes the public an explanation and apology for giving his unequivocal backing to a minister he knew had knowingly lied to the country when he claimed that the iPad had only been used for work purposes.

“On Wednesday, the First Minister was still parroting the line that this was an honest mistake related to an old SIM card, when he knew the truth.”

Mr Ross added: “The fact is the Health Secretary has lied and covered up throughout this scandal and the First Minister appears to have aided and abetted him.

“The country can see Michael Matheson’s position is untenable. If Humza Yousaf refuses to sack him, he is condoning ministers lying to the public and misleading parliament.”