Leamonth, who will represent Scotland in the 800m at the Commonwealth Games in the summer, was representing the host nation in the event, and he won the race in a time of 1.16.48
He produced a fantastic finish, storming off the last bend to pip Kenyan Jeremiah Mutai, representing the Commonwealth, who ran a personal best, and Great Britain international Andrew Osagie, who set a season’s best time.
Some athletics journalists wrote that Leamonth ‘showed maturity above his years to snatch a surprise victory, much to the delight of the Glasgow fans.’
Afterwards Learmonth said: “We’re here and we’re a nation that want to perform on the day.
“We don’t just want to turn up for the tracksuit, but we want to represent Scotland with great pride and honour.
“The roar of the crowd on the start line was absolutely unbelievable.”
Later he Tweeted: ‘A new national record and a UK U23 record, I can’t believe it.
“Thanks to everyone for the messages of congratulation and support.”