A rare 17th-century manuscript journal documenting Captain John Narbrough’s secret expedition to Spanish America and the Pacific has been placed under a temporary export ban, giving UK

institutions time to secure what is being described as a vital piece of national history.

The handwritten journal, valued at more than £800,000, records Narbrough’s voyage as captain of HMS 'Sweepstakes' from 1669 to 1671, including his mission to Valdivia in modern-day Chile. The Reviewing Committee on the Export of Works of Art and Objects of Cultural Interest recommended the export bar, citing the document’s outstanding importance to English history and the development of mapping and navigation.

Almost entirely written in Narbrough’s own hand, the manuscript contains 28 hand-coloured illustrations, along with numerous pen-and-watercolour sketches in the margins. It offers a vivid account of the explorer’s encounters with local people and wildlife, while shedding light on England’s maritime ambitions in South America during the late 17th century.

Experts say the journal provides crucial context for later, better-known expeditions by figures such as George Anson, James Cook and George Vancouver, helping to trace the growing relationship between navigation, science and state-sponsored exploration.

Culture minister Baroness Twycross urged a UK public institution to acquire the manuscript, calling it “a unique and key piece of our nation’s rich history” that predates the great Pacific voyages of the 18th century by almost 100 years.

Committee member Caroline Shenton described the journal as being of “absolutely outstanding importance”, warning it would be “deeply sad” if it were lost overseas. She said the acquisition would fill a “gaping hole” in the national record and restore Narbrough to his rightful place among Britain’s greatest explorers.

The committee concluded that the journal met the first and third Waverley criteria, reflecting its close connection to British history and its exceptional value for the study of exploration, cartography, science and anthropology.

The export licence decision has been deferred until 14 March 2026. During this period, UK buyers will have the opportunity to raise the recommended purchase price of £843,361.83. If an option agreement is signed, a further four-month deferral period will apply.