THE SNP’s refusal to suspend Nicola Sturgeon’s husband amid a police investigation may amount to “unlawful discrimination”, an MP has said.

Joanna Cherry KC said other members of the party had been suspended over relatively smaller issues, yet Peter Murrell remained within the fold.

“He is very lucky that his SNP membership has not been suspended pending the outcome of the police investigation,” she said, adding: “Others have not enjoyed the same leniency.”

Mr Murrell was arrested and questioned by police officers last week as part of a long-running investigation into the SNP’s finances.

Mr Murrell, who quit as SNP chief executive last month after the media were misled about the party’s falling membership, was later released without charge.

Officers also searched the Glasgow home he shares with Ms Sturgeon and seized a luxury £110,00 motorhome from outside his 92-year-old mother’s house in Dunfermline.

It was later reported that the SNP bought the vehicle as a Covid compliant ‘battle bus’ ahead of the 2021 Holyrood election, but never used it.

Police Scotland is looking at whether £660,000 raised specifically to fight a second independence campaign may have been spent on other things.

On Tuesday, SNP leader and First Minister Humza Yousaf said the SNP had decided not to pay Mr Murrell’s legal fees as he was no longer its chief executive.

However he also ruled out Mr Murrell being suspended for now.

He said: “I’m not asking Peter Murrell to resign or suspend his membership. I tend to operate on the premise that people are innocent until proven guilty.”

However, writing in the Herald’s sister paper, The National, Ms Cherry said the approach to Mr Murrell was not consistent with the party’s recent treatment of other members.

She said: “Others have not enjoyed the same leniency. 

“One thinks of Michelle Thomson, never arrested, ultimately exonerated but thrown under the bus at the first hint of trouble. 

“Tim Rideout was suspended for six months for an ill-judged tweet. 

“Gender-critical women have been suspended indefinitely for tweets exercising their right to freedom of belief and freedom of speech.

“This difference in approach is neither fair nor in accordance with the principles of natural justice. In some cases, it might even amount to unlawful discrimination.”

Ms Thomson was suspended while police looked at her property dealings, while Mr Rideout was suspended after a row over a ‘racist’ tweet about then Home Secretary Priti Patel.

Ms Cherry, the MP for Edinburgh South West, said the SNP’s disciplinary procedures needed to be clarified.

She went on: “The anomalies in how the SNP’s complaints and disciplinary process has been applied are part of a much wider problem with the party’s management which is now in the public domain because of recent events. 

“I am conscious from my conversations with party members and from my mailbox that what has occurred has been deeply shocking for many. 

“For others, including myself, while some of the visuals have been shocking, the fact that there is a significant problem has come as no surprise.”