Launched in 1925, the Mary Scott was approaching middle age by lifeboat standards when she participated in the Dunkirk evacuation. She was towed to Dunkirk by the paddle steamer Empress of India, accompanied by two other small boats. Together, they rescued 160 men and transported them to their mother ship. Upon returning fully laden to Dover, the Mary Scott made a subsequent journey carrying fifty men to another transport vessel.

During the operation, the Mary Scott's engine broke down and could not be restarted. As a result, she was beached and abandoned at La Panne, east of Dunkirk. Sub-Lieutenant Stephen Dickenson, her commander and a former Royal National Lifeboat Institution (RNLI) Inspector of Lifeboats, along with the crew, returned to Dover aboard the Louise Stephens, the Great Yarmouth and Gorleston lifeboat.

The Mary Scott was later refloated and brought back to England. Over the following twenty-eight years, she saved forty-seven lives. Serving as the Southwold lifeboat, she was launched on thirty additional occasions before the station closed in 1940. Subsequently, she continued her service within the RNLI relief fleet, participating in fifty-two further rescues.

In 1953, the Mary Scott was sold out of service and renamed Atenua. Six years later, she was converted by a jewellery manufacturer. During the 1990s, her owner kept her on the River Medway and restored her original name, Mary Scott.

After several years of inactivity, the vessel was purchased and restored by her current owners in 2007. She took part in the 2010 and 2015 Dunkirk return events and was featured in the 2017 Christopher Nolan film Dunkirk.