Lady Warren was a French prize that a Briton purchased c. 1804 and that served as a hired armed ship on a contract to the Royal Navy from 7 May 1804 into mid-1807. She served in the Channel, primarily out of Plymouth, convoying and cruising. During 1805 she detained numerous merchant vessels. She left naval service in early-to-mid 1807 and became a letter of marque merchantman. She was wrecked, without loss of life, in November.