She has won numerous medals for her country as well as being a swimming coach of the year for her work with Adam Peaty in Derby and later Loughborough.

A long lasting international career started at the 1995 European Youth Olympics in Bath, where she won four gold medals.

Marshall was ranked number one in the world in 2004 after breaking the British 200 m freestyle record to ensure selection to the 2004 Olympic Games in Athens.

At the 2008 Short Course World Championships in Manchester, she came third as part of the British women's 4×100 m freestyle relay team.

[9] Marshall was appointed Member of the Order of the British Empire (MBE) in the 2021 Birthday Honours for services to swimming and charity.