She represented Great Britain at the 2012 Olympic Games in London, and won an Olympic bronze medal in the 4 x 400 metres relay at the 2016 Games in Rio de Janeiro.
Doyle is the Scottish record holder for the 400 metres hurdles with 54.09 sec (2016) and the indoor 400 metres with 51.45 sec (2013).
She is the 2014 European Champion and a three-time Commonwealth silver medalist (2010, 2014 and 2018) in the 400 metres hurdles.
Her other relay honours include World Championship silver medals in 2013 and 2017, and the bronze medal in 2015.
She was also a world and European indoor medalist in the 400 metres.