Mimosa was requisitioned in 1940, along with many other pleasure boats, for Operation Dynamo. After being provisioned and fueled at Dover, she departed under the command of Lieutenant Commander Dixon to make three trips to the beaches off Dunkirk. Her involvement in the evacuation remained undisclosed for 57 years until her current owners, Colin Messer and Jane Percival, conducted detailed research and revealed her history.

Immediately following Dunkirk, Mimosa was chartered as an Auxiliary Patrol Vessel for £21 per month and was renamed Ocelot, a change intended to conceal her role in the evacuation. The name Ocelot was retained after the war and remained when she was first registered in 1951, sixteen years after her completion at Thornycroft's yard in Hampton-on-Thames. She was one of four identical hulls constructed there; two returned from Dunkirk, while the other two did not survive the war.

In 1996, Colin Messer and Jane Percival became the fourteenth registered owners in 45 years. The previous owner had completed a thorough restoration of the hull and begun fitting out the interior. Colin Messer, a professional boatbuilder, rebuilt the wheelhouse to reflect the original design, reconstructed the teak skylights, recaulked the iroko decks, and installed new systems and engines. By 1999, restoration was approximately two-thirds complete, with an estimated additional 1,000 hours required to finish the interior.

Subsequently, Ocelot reverted to her original name, Mimosa. In 1999, she cruised alongside other Dunkirk Little Ships in preparation for her return to Dunkirk in June 2000, commemorating the Diamond Anniversary of the evacuation. She completed the 2015 Dunkirk return under the care of new owners.

Mimosa was featured individually on a series of stamps titled Little Ships of Dunkirk, issued by Palau in 2015 to mark the 75th anniversary of Operation Dynamo. She has made several recent appearances at the Thames Traditional Boat Festival in Henley and was featured in the 2017 film Dunkirk. Currently moored in Bristol, Mimosa remains an active member of the Association of Dunkirk Little Ships (ADLS).

Additional Information

• In 2012, Mimosa changed ownership but remained moored in Windsor until relocated to her new home port at Bristol Docks. The vessel received extensive maintenance in preparation for the Queen's Jubilee Pageant.
• Alan Johnston, whose father purchased the vessel in 1955 when she was named Ocelot, noted that she was fully restored and cruised extensively in the west of Scotland. The original petrol-paraffin Thornycroft engines were replaced at that time.
• The vessel’s original bell was preserved by the family of a former owner prior to her requisition for Dunkirk.
• By late 2009, Mimosa had been fitted with new Isuzu diesel engines and was completing her refit in preparation for the 2010 Dunkirk commemoration.
• Visitors and enthusiasts have praised the vessel’s condition and the dedication of her owners in preserving her historical significance and operational status.