Rupert Soames, the grandson of the Conservative wartime prime minister Sir Winston Churchill, has donated nearly £5,000 to a prospective Liberal Democrat MP. Soames, who spent most of his career in the City, most recently running outsourcer Serco, gave £4,999 in financial support to the Liberal Democrats in March, according to official records released this week. Soames said he made the donation to directly support Angus MacDonald, a Scottish businessman and Highland councillor who has been selected to contest the Ross, Skye and Lochaber seat in the next general election. MacDonald, a published author and entrepreneur, had been expected to contest for the seat with Ian Blackford, the former SNP Westminster leader. However, Blackford said this week he would be standing down at the next election. Blackford held the seat since 2015 and took over as Westminster SNP leader from Angus Robertson in 2017, before being ousted late last year. Soames told the Guardian: “I have donated to a candidate who is standing in the constituency where I live in Scotland, Angus MacDonald, in a personal capacity.” Soames said he had known MacDonald for 25 years and the pair were “almost neighbours”. “He is a longstanding friend. I respect that he wants to go into politics. He has had a very good and long career as an author and a supporter of the businesses on the west coast [of Scotland],” Soames said. Soames’s father, Sir Christopher, was a Conservative minister in the 1960s while his brother, Nicholas, was a Conservative MP until 2019. Soames’s wife, Camilla, donated £4,995 to the Conservatives in the run-up to Boris Johnson’s election victory in 2019. Soames said that in Scotland it was convention to “support individuals rather than parties”. Asked whether he thought people would be surprised at his donation given his family history, Soames said: “No, they probably understand Scottish politics – a lot of people vote across party lines.” Soames said he believed that MacDonald’s chances of gaining the seat – which was once held by the former Lib Dem leader Charles Kennedy – were “rather better” since Blackford’s announcement this week. Soames earned about £30m at Serco, which he took over in 2014 after a scandal over electronic tagging and left in early January 2023. He was forced to defend the outsourcer’s work on setting up the NHS coronavirus test-and-trace system during the pandemic. Soames’s donation emerged in quarterly Electoral Commission data released this week. The data showed that the Conservative party raised more than £12m in donations in the first three months of the year, including £5m from Egyptian-born billionaire Mohamed Mansour. UK political parties raised nearly £21m in donations and public funds in the first quarter of the year. Other donations from business figures included £500,000 to the Labour party from Gary Lubner, the former boss of Autoglass’s owner. Labour also received £16,000 from Ian Rosenblatt, the founder of the eponymous law firm, and £25,000 from Lord Waheed Alli, the media tycoon and Labour peer. The Conservatives received £50,000 from Firefly Capital, which is controlled by hedge fund tycoon Hilton Nathanson; £30,000 from Fenchurch Advisory Partners, founded by City dealmaker and former Conservative party treasurer Malik Karim, and nearly £250,000 in cash and staffing costs from Richard Harpin, the founder of repairs business Homeserve. Edward Bonham Carter, the brother of the actor Helena Bonham Carter and former deputy chairman of fund manager Jupiter, donated £2,000 to the Lib Dems, his first donation since 2013. His cousin, Jane Bonham Carter, is a Lib Dem politician.