British sprinter Darren Campbell announced his retirement after winning a low-key 100m race at the inaugural Celtic Cup in Grangemouth.
Campbell surprised UK Athletics with his decision
The 32-year-old was expected to say his farewell at the two-day meeting in Birmingham at the weekend.
"That was definitely my last race," said Campbell, who has won individual and 4x100m relay medals at Olympic, World, European and Commonwealth level.
Scotland won the match, with Ireland second and Wales third.
Campbell said: "I got a bit misty-eyed in the warm-up when I realised it was all going to come to a close.
"It's good to end your career with people who are just going out to do their best. I decided to call it a day tonight because I'm emotionally drained."
Campbell sparked controversy at the recent European Championships when he refused to take part in a lap of honour after winning gold in the 4x100m relay.
He said it was over the inclusion of Dwain Chambers in the GB team after his two-year drugs ban.
Campbell's retirement announcement came as a shock to UK Athletics performance director Dave Collins.
"We were making arrangements to say farewell to Darren with a big bang celebration in Birmingham.
"He's been a great servant of the sport and I am sure he will retain his interest as his input has proved invaluable in the past.
"He is already deeply involved in street athletics and of course he was here earlier this week, as an ambassador meeting the next generation of British athletes."
Team captain Lee McConnell won the 200m, Gemma Nicol lifted the 400m prize and Jo Ross triumphed over 800m as Scotland amassed 43 points.
Ireland picked up 32 points, with Wales bringing up the rear on 25 points.
Veteran champion Marlene Ottey was too good for the rest of the field in the 100m.
American Tyree Washington, a former World Indoor 400m champion, also announced his retirement after finishing last in the 600m race.