RISHI Sunak has asked his independent ethics adviser to look into the Nadhim Zahawi tax case, as “clearly in this case there are questions that need answering”.

On a visit to a hospital in Northamptonshire, the Prime Minister told reporters: “Integrity and accountability is really important to me and clearly in this case there are questions that need answering.

“That’s why I’ve asked our independent adviser to get to the bottom of everything, to investigate the matter fully and establish all the facts and provide advice to me on Nadhim Zahawi’s compliance with the ministerial code.

READ MORE: SNP in letter to Rishi Sunak to 'undertake deep clean' of government

“I’m pleased that Nadhim Zahawi has agreed with that approach and has agreed to fully co-operate with that investigation.”

Rishi Sunak said Zahawi will remain Tory Party chairman while he is under investigation over a possible breach of the ministerial code.

Asked if Zahawi should not stand down during the investigation, Sunak said: “As is longstanding practice, he will continue to play the role he does.”

This is a significant change in the Prime Minister's position after he told the House of Commons last week that Zahawi had already addressed the matter. 

Now, Sunak's ethics advisor Sir Laurie Magnus will be charged with investigating whether Zahawi broke the ministerial code. 

READ MORE: Air pollution figures ‘show benefits of low-emission zones’

It is estimated that Zahawi paid a nearly £5 million penalty to HMRC in a dispute over his tax affairs. 

Zahawi has said that it was a "careless" error and not deliberate. 

He has now vowed to cooperate with the investigation. 

In statement he said: “I welcome the Prime Minister’s referral of this matter to the independent adviser on ministerial standards. I look forward to explaining the facts of this issue to Sir Laurie Magnus and his team.

“I am confident I acted properly throughout and look forward to answering any and all specific questions in a formal setting to Sir Laurie.

“In order to ensure the independence of this process, you will understand that it would be inappropriate to discuss this issue any further, as I continue my duties as chairman of the Conservative and Unionist Party.”

The First Minister Nicola Sturgeon said that Zahawi’s position was “untenable”:  

“I know what the Prime Minister has said, which seems to me be more about kicking it into the long grass rather than addressing it.

“I think his position, the former chancellor’s position, is untenable. I think he should resign his current position as chair of the Conservative Party.

“It seems to be the case that while he was chancellor he settled a seven-figure tax bill with HMRC, which included a very significant penalty.

“Now that means, as far as I can see, that there must have been something untoward about his tax affairs to a very large tune in terms of the amount of money involved.”