Filming started in March 1955. Filming was done in Portugal and at several Royal Marine establishments, with the
Commandant-General Royal Marines training the actors for drill and canoe handling. The training camp scenes in the film were shot at
Eastney Barracks in
Southsea,
Hampshire. Many of the barrack buildings seen in the film still exist including the military buildings further up the beach where the scene to dispose of the live explosive device before its fuse time expired was filmed. The
Royal Navy ships, and , were used to portray a German anti-submarine vessel dropping
depth charges. This resulted in the ship dropping the first depth charges being seen with F383 on its side but in the next shot it has F384 on the side. The two corvettes were both scrapped shortly after filming (in 1956 and 1958 respectively). Studio scenes were shot at Shepperton. The limpet mine scenes were filmed in the King George V Docks in North Woolwich and many of the other scenes were filmed on the adjacent bomb sites and at derelict houses in the area.
Lieutenant Colonel Herbert "Blondie" Hasler, RM, the leader of the real-life raid, was seconded to Warwick Films as a
technical advisor. Ex-Corporal
Bill Sparks, the other survivor of the raid, was also an advisor. "It was not a happy picture at all," said Forbes. "Ferrer was a megalomaniac." The film briefly uses several railway locations including the level crossing (Military Road) adjacent to
Fort Brockhurst railway station on the (by then "goods only") Gosport branch in Hampshire. The station buildings and former platforms survive today as a private residence. As he cycles south, Ferrer has to wait for a passing northbound train (a van hauled by
LSWR T9 class locomotive 30729) so he takes the opportunity to abandon his bicycle in favour of a ride in the rear of a fish lorry. Later, Ferrer steals the fish lorry only to abandon it at Shepperton Station (Surrey) in order to catch a just-departing Up train allegedly to Portsmouth, steam train noises being provided on this otherwise electric branch. In another sequence, David Lodge ducks out of sight into a brick bus shelter alongside the North Woolwich Branch. This was possibly at the footbridge opposite Fernhill Street on Albert Road, west of North Woolwich station. David Lodge is also filmed running over the road bridge adjacent to
Chertsey railway station where a Southern electric train can be seen drawing into the Up platform. The film location where Marine Cooney leaps off a road bridge into a coal wagon (within a Southampton-bound goods train hauled by an
LSWR S15 class locomotive) is Chertsey Road, Addlestone, with Egham Hill and Chertsey in the background as well as Addlestone Cemetery beyond the two fields to the left of the railway line. Now numbered the A318, Chertsey Road and this location are almost unrecognisable following road realignments for the building of the A317 St Peter's Way along with subsequent property developments. Trevor Howard and David Lodge nearly drowned while filming a sequence in a canoe when the canoe overturned. During production the film was sometimes known as
Survivors Two. The then-famous British singer, Yana (Pamela Guard), is shown in a cameo role as a sweetly-singing blonde Wren (
Women's Royal Naval Service member) in a pub scene, shortly before a brawl erupts. In order to get permission to film in Portugal, Warwick Films had to make a documentary about the country,
April in Portugal. This was directed by Euan Lloyd, who worked for Warwick, and featured Howard. The budget was £267,406 plus fees for Ferrer, Broccoli and Allen.
Reshoots Irving Allen decided Maibaum's script did not have enough comedy, so he had Forbes rewrite Maibaum's revision and direct some sequences without telling Ferrer. When Ferrer found out, he left the film. Forbes later said, "I was responsible for reshooting a great deal of them, without Ferrer's knowledge, because the producers weren't happy with the way it was going." He says these scenes involved Howard and were directed by Allen. Forbes was on set during these which he said "was really valuable training which would serve me well later on" when he became a director. During filming, the two survivors of the mission told the producers they had no idea what the cargo was in the ships that were destroyed. After the film was completed, Broccoli claimed that the
Duke of Edinburgh and
Lord Mountbatten told him the contents of the cargo were radar equipment bound for Japan. Broccoli thought this made the story more interesting and had additional sequences shot to be added to the release print. This cost an extra $5,600. ==Reception==