Prime Minister Rishi Sunak has been reported to police in Scotland over comments made about former first minister Nicola Sturgeon in his Tory conference speech.

Mr Sunak sought to make fun of the former SNP leader after she was arrested and questioned as part of Police Scotland's investigation into her party's finances – dubbed Operation Branchform.

Ms Sturgeon was released without charge following her arrest back in June.

Now Chris McEleny, the general secretary of the rival pro-independence Alba Party, has reported Mr Sunak to the force for contempt of court allegations, as the Prime Minister's comments come amid a live police investigation.

The Conservative leader, who was addressing his party's conference in Manchester, made the comments as he claimed the union between Scotland and the rest of the UK was "the strongest it has been in a quarter of a century", with the Prime Minister adding that "the forces of separatism are in retreat".

But Mr McEleny said that "Operation Branchform should be free to pursue its investigation fearlessly without interference from Rishi Sunak", adding as a result he was "formally complaining about the offence of Contempt of Court", requesting police to investigate this.

The Alba general secretary stated: "The Prime Minister is commenting on, and making an assumption about a live Police Scotland investigation.

"In Scotland contempt applies from arrest, not from charging. Operation Branchform is investigating serious matters of the utmost importance the Scotland and trust in politics.

"It is too important a matter to allow interference from the Prime Minister in this act of contempt when many people await the facts of Police Scotland's investigation."

Both Police Scotland and Downing Street have been contacted for comment.