Former Olympic and world 400 metres champion Christine Ohuruogu admitted it is the right time to quit after announcing her retirement.
The 34-year-old won Olympic gold at Beijing 2008 and silver in London four years later.
She also claimed world titles in 2007 and 2013, but her last major medal came two years ago, with 4x400m bronze at the Rio Olympics.
Ohuruogu, who is halfway through a law degree at university, said in a statement on her website: "Today is the start of the British Championships and, as I won't be there competing, I feel it is a good time to formally announce my retirement from competitive athletics.
"I didn't feel ready to retire after last season but a combination of my studies and a niggling injury restricted how much training I was able to do this year.
"I end my career with four Olympic medals and five World Championships medals.
"Athletics has been my passion for so long and I am proud to call myself an athlete."