His father, Tristian, who is also his coach, added: “To see your son achieve something like that at such a young age makes the whole family so incredibly proud.”
Roberts, who improved his climbing on a DIY wall built in his parents’ garden, is part of Spider Climbing Group, based in Guildford.
Emma said while her brother had always loved climbing, nobody predicted his rise to success.
“We just thought he was pretty good at climbing, and then the next thing you know, he’s winning a gold medal in his first Olympics,” she said.
Roberts’ brother, James, added: “As soon as Toby won that medal, he didn’t believe it. We didn’t believe it. There are no words to describe that feeling.”