Rishi Sunak has been reported to police in Scotland over a joke he made about Nicola Sturgeon in his Conservative party conference speech. Sunak attempted to make fun of the former SNP leader and first minister after she was arrested and questioned as part of Police Scotland’s Operation Branchform investigation into her party’s finances. Sturgeon was released without charge after her arrest in June. She has denied any wrongdoing. In his conference address, Sunak claimed the union between Scotland and the rest of the UK was “the strongest it has been in a quarter of a century”. He added: “Nicola Sturgeon wanted to go down in the history books as the woman who broke up our country. But it now looks like she may go down for very different reasons.” Chris McEleny, the general secretary of the rival pro-independence Alba party, said he had reported Sunak to Police Scotland for contempt of court allegations, as the prime minister’s comments come amid a live police investigation. McEleny said: “Operation Branchform should be free to pursue its investigation fearlessly without interference from Rishi Sunak.” He added: “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 to 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.” Downing Street said it would not be commenting. Police Scotland has been contacted for comment.