|Representing Great Britain|
|Women's World Games|
|1930 Prague||800 metres|
|1934 London||800 metres|
|British Empire Games|
|1934 London||880 yards|
|1934 London||Javelin throw|
|1938 Sydney||Javelin throw|
At the 1934 Empire Games she won the gold medal in the 880 yards event as well as in the javelin throw competition, an unorthodox combination.
Four years later she won the bronze medal in the javelin throw event at the 1938 Empire Games. She also participated in the 220 yards contest but did not start in her semi-final heat.
She was the inaugural winner of the (unofficial) ladies race at the International Cross Country Championships. She was also twice a medallist in the 800 metres at the Women's World Games, taking gold in 1930 before returning for a bronze medal in 1934.
Nationally, she was a ten-time champion at the Women's Amateur Athletic Association Championships. This included three straight 880-yard titles from 1930 to 1932, two 800 m titles, the first ever mile run in 1936 and the following year in 1937, a 1937 javelin title and two cross country titles.
Lunn had two world records ratified by the International Women's Sports Federation (FSFI): 3:04.4 minutes for the 1000 m in 1931 and 3:00.6 minutes over the same distance in 1934. Four of her performances over the mile were later recognised as world best times.
- "Birchfield Harriers Sporting Tales". Archived from the original on 9 June 2016. Retrieved 18 May 2016.
- Commonwealth Games history. Athletics Weekly. Retrieved on 2015-04-03.
- Commonwealth Games Medallist - Athletics (Women). GBR Athletics. Retrieved on 2015-04-03.
- International Cross Country Championships. GBR Athletics. Retrieved on 2015-04-03.
- Women's World Games. GBR Athletics. Retrieved on 2015-04-03.
- WAAA Championships. GBR Athletics. Retrieved on 2015-04-03.
- British World Record Breakers. GBR Athletics. Retrieved on 2015-04-03.