The intervention by Michael Ellis means that the "Bust of Peace" cannot be exported from Britain to enable a home buyer to be found to match 5.3 million pounds (6.9 million U.S. dollars) offered by an overseas buyer.
The white marble "Bust of Peace" is considered to be an original work by Antonio Canova, one of the greatest 19th century sculptors.
The neo-classical bust, one of a handful of original works by the Italian neoclassical artist that remain outside museum collections, was sold to a private buyer at Sotheby's in July 2018. Until then, it had been more than 200 years since it had last been seen in public.
"The 'Bust of Peace' combines a crucial moment in our history with beauty and elegance, pointing to a more peaceful future ahead. It is essential that we do our best to save this superb item for the benefit of the nation," Ellis said in a statement Friday.
The Department for Digital, Culture, Media and Sport (DCMS) said the work can be seen to symbolise the return of peace to Europe after years of struggle and unrest during the Napoleonic era, which culminated in the Battle of Waterloo, where Napoleon was defeated.
It was carved between 1814-15 and may have been given to John Campbell, Lord Cawdor, in part to thank him for his help in repatriating art looted from Italy by the French armies during the Napoleonic Wars.
It was the first such bust to reach Britain, and the first to be presented to a British patron after Napoleon's defeat.