It was based upon the book written by Lawrence Earl. The film was known in the US by the alternative titles Battle Hell, Escape of the Amethyst, Their Greatest Glory and Yangtze Incident. Non-English language titles include the direct German translation of Yangtse-Zwischenfall, and Commando sur le Yang-Tse in France. In Belgium it was known as Feu sur le Yangtse (French) and Vuur op de Yangtse (Flemish/Dutch), both meaning "Fire on the Yangtse".
The film was entered into the 1957 Cannes Film Festival.
On 19 April 1949, the Royal Navy frigate HMS Amethyst sails up the Yangtze River on her way to Nanking, the Chinese capital, to deliver supplies to the British Embassy. Suddenly, without warning, People's Liberation Army (PLA) shore batteries open fire and after a heavy engagement, Amethyst lies grounded in the mud and badly damaged. Fifty-four of her crew are dead, dying or seriously wounded while others deteriorate from the tropical heat and the lack of essential medicines, including the ship's captain, who dies of his wounds. An attempt to evacuate the wounded is only partially successful - the officers of the Amethyst become aware that two Petty Officers were captured by the PLA and are being held at a nearby military hospital. After taking stock of their position, the Captain is replaced by Lieutenant Commander John Kerans (Richard Todd), who had been serving as a Naval attaché in nearby Nanking but rushes to the beleaguered ship to take command.
After an attempt by HMS Consort to tow Amethyst off the mud bank fails, Lieutenant Commander Kerans decides to risk steaming down the Yangtze at night without a pilot or suitable charts. Before they can leave, however, the local Communist official Colonel Peng (Akim Tamiroff) makes contact with the Amethyst and at a meeting between senior officers makes his position clear: either the British government releases an apology accepting all responsibility for the entire incident, or the Amethyst will remain his prisoner. Similarly, he will not allow the two wounded sailors to leave unless they give him statements declaring the British to have been the transgressors, which they refuse to do. Kerans dismisses his demands but is able to manipulate Peng into the release of the Petty Officers; meanwhile, as talks progress he has the ship patched up and its engines restored. After some subtle alterations to the ship's outline to try to disguise her, Amethyst slips her cable and heads downriver in the dark following a local merchant ship, which Amethyst uses to show the way through the shoals and distract the PLA. When the shore batteries finally notice the frigate escaping downriver, the merchantman receives the brunt of the PLA artillery and catches fire, while Amethyst presses on at top speed.
Encountering an obstruction in the river in the form of several sunken ships, and having no proper equipment for charting a safe course, Kerans uses both intuition and luck to slip through before then reaching the guns and searchlights of Woosung. After she is inevitably spotted, the Amethyst is forced into a lengthy fight with the PLA batteries as she simply flees with all guns blazing, heading for the mouth of the river just beyond. As day dawns she finally reaches the open ocean, where she greets HMS Concord with the message "Never repeat never has another ship been so welcome". She also sends a signal to headquarters: "Have rejoined the fleet south of Woosung ... No major damage... No casualties....God save the King!" The film then ends with scrolling text reciting verbatim the message sent the very same day from King George VI, commending the crew for their "courage, skill and determination".
The film was produced by Herbert Wilcox who raised part of the budget from RKO and American investors.
HMS Amethyst was going to be broken up. However the filmmakers got to it in time. It was brought out of store to participate in the film as herself. As the Amethyst's main engines were no longer operational, her sister Black Swan-class sloop HMS Magpie stood in for shots of the ship moving and firing her guns.
John Kerans, by then promoted to commander, served as technical advisor during the production. During production live charges detonated and the Amethyst almost sunk but Kerans managed to save the ship.
The HMS Essex was used to double the Amethyst in some shots. During filming it was called away to Egypt during the Suez Crisis. Michael Anderson and his film crew managed to get a necessary shot of the Essex as it left to go overseas.
The destroyer HMS Teazer stood in for both HMS Consort and HMS Concord. As Consort, down from Nanking, she wore the correct pennant number D76; as Concord, up from Shanghai, her pennant number was covered by Union flags. Teazer is depicted firing her guns broadside and turning at speed in the narrow confines of the Stour estuary as Consort attempts to get a towing line to Amethyst under heavy gunfire.
The rivers Orwell and Stour - which run between Ipswich and Manningtree, in Suffolk, England - doubled as the Yangtze River during the making of this film. The Chinese PLA gun batteries - depicted by old Royal Navy field guns on land carriages - were deployed on the sloping banks of the Boys' Training Establishment HMS Ganges which was sited at Shotley Gate, facing Felixstowe on the Orwell, and Harwich on the Stour, where the rivers converge.
During filming, Wilcox's bank told him they would not accept a guarrantee of ₤150,000 from RKO London unless supported by its parent company in New York. This did not happen and Wilcox had already spent ₤70,000 of the ₤150,000. He went personally into debt for £150,000. The National Film Finance Corporation stepped in to make up the short fall. However Wilcox would be plagued with financial troubles for the rest of his career.
The film had its premiere with the Lords of the Admiralty and Prince Philip, Duke of Edinburgh in attendance. It also screened at the Cannes Film Festival.
The film was the 15th most popular movie at the British box office in 1957. Wilcox thought the film's box office performance was hurt by the fact that its general release came so long after the premiere and after release of The Battle of the River Plate (1956). In 1967 when he wrote his memoirs Wilcox said film was yet to recover its production costs.