[2] Lee first represented Great Britain in 2010 at the World championships in the Netherlands where she won silver in the women's 4x100 individual medley 34-point relay and gold in the 100m Breaststroke SB9.

Although selected Harriet missed out on competing at the European championship in 2011 through illness.

In the 2012 British Championships in London, she won a gold medal in the 100m Breaststroke SB9 competition and on 8 September 2012 at the 2012 Paralympics she won a bronze medal in the same event having broken the European record in the heats with a time of 1min 19.44 secs.

[2] In the 2016 Olympics, held in Rio de Janeiro, Brazil, Lee received her second silver medal.

On 8 September 2016 she received the silver medal in the 100m Breaststroke SB9 with a time of 1 min 16.87 secs.