A Cambridge student has been expelled from the university’s Conservative Association for trying to burn a £20 note in front of a homeless man.

Ronald Coyne, a law student and distant relative of Nicola Sturgeon, Scotland’s first minister, was ejected from the association after footage of the incident was published. It showed him, dressed in white tie and tails, trying to set fire to the money.

Mr Coyne’s mother, Sandra McLaughlin, said: “I don’t really know why he’s done something so thoughtless and cruel. He did two years of volunteering at Stockbridge shelter homeless shop in Edinburgh when he was still at school. It’s very surprising. We’re just a normal family. We’re not toffs, he’s not a toff.”

Mr Coyne, of Pembroke College, is also