During her fourth operational patrol, which begun in the middle of December 1950 aircraft from Theseus sighted numerous land vehicles, in the North of the seperated country, in what was a quintessential winter scene, with heavy snow covering the area. The destruction was tremendous, with many vehicles, from jeeps to tanks and trucks being destroyed. Soon afterwards, Chinese troops inadvertently became the target of ferocious attacks from aircraft flying off the Theseus, who after the end of the fourth tour had chalked up over 1630 hours in the air, and astonishingly fired over 1,400 rockets.
The next year, on the 5th of January, Theseus commenced her fifth operational patrol, supporting the American 25th Division who were fighting south of Osan in South Korea. On the 15th January, a Lietenant Highett landed to create an astonishing milestone of 1000 accident-free landings on Theseus. The CAG (Carrier Air Group) were awarded the Boyd Trophy for a remarkable operational tour of duty that included many firsts for pilots and aircew, not to mention the ship itself. The sixth operational patrol commenced in late January, involved a tragic incident. On the 26th January, an aircraft flown by Lieutenant A.C. Bevan, appeared to almost shudder, before spinning out of control and into the sea. The C Class destroyer and WWII veteran HMS Cossack made her way to the location of the crash but to no avail. Another pilot was shot down soon afterwatds, though compared to the tragedy of the former, was far more fortunate. The aircraft that was flown by Lieutenant Keighley-Peach was hit numerous times by anti-aircraft gunfire, forcing him to ditch the aeroplane in a valley, in an area near to Tongduchon-ni. There he hid, awaiting rescue for what must of seemed an eternity, where in reality was about 90 minutes. An American helicopter soon flew in, picking the Lieutenant up, while other aircraft from Theseus flew a CAP (Combat Air Patrol) over the area, incase of attack by North Koreans. It was a scene almost plucked from The Bridges at Toko-Ri though fortunately no casualties were incurred. Another dubious distinction of the sixth operational tour came on the 2nd February, with a landing that halted what would of been the 1464th accident-free landing, when a Sea Fury burst a tyre while landing, straining the fuselage at the undercarriage attachment points.
The seventh operational patrol started off tragically. Fairy Fireflies, after returning from reconnaissance missions, streching from Seoul to Pyongyang and other areas, landed with three of the Fireflies guns accidently firing, one fatally wounding Petty Officer Airman J.F. Wigley. He was buried at sea the following day, with full Naval Honours. Further reconnaissance missions were flown, as well as CAS (Close Air Support) for IX Corps in the Wonju area.
The eighth operational patrol, beginning on the 4th March saw much of the same, with patrols from the now familar area of Chinnampo to Kuhsa-Sung, to create the illusion of an impending amphibious assault. Two more crashes occurred, the first inccured no casualties though the second proved to be fatal. During armed recconaisance near Chanyong, Lieutenant G.H. Cooles and Flight Lieutenant D.W. Guy, both from the RAF, crashed while returning to Theseus. A number of Sea Furies proceded to fly a CAP (Close Air Patrol) over the crash site, but sighted no survivors.
The ninth operational patrol begun with and just days after the start on the 24th March, another aircraft was shot down. Lieutenant-Commander Gordon-Smith's aeroplane being shot down by an armoured piercing bullet, damaging his fuel tank, leaving him no other option but to land at Suwon. Further reconnaissance and CAS (Close Air Support) missions were flown, including an attack on six enemy vessels.
The tenth operational patrol began on 8th April operating in the Sea of Japan with the accompanying American carrier Bataan, together with a Commonwealth/US destroyer screen, comprising HMS Consort, HMAS Bataan, HMCS Huron, USS English and USS Sperry. On the 10th April, two Sea Furies were attacked by American Corsairs in a friendly-fire incident. with one being seriously damaged, the other after much manouevering escaped unhurt. Two other Sea Furies who were performing near-by reconnaissance duties heard the call for assistance, and while on the way there pilot H.Johnson's aircraft was shot down. He was believed dead, until it was later found out that he had been taken prisoner. Another pilot, Lieutenant E. Julian who was searching for Johnson's aircraft was shot down by flak. Luckily , the Lieutenant escaped. Two more aircraft were show down. The first, was shot down forty miles from Theseus and was soon rescued by helicopter, the second, again hit by flak crashed initially into a paddy field, then skidding straight into a dry river bed. North Koreans troops peppered his aircraft with small arms fire. The other aircraft from his flight acted as a RESCAP (Rescue Close Air Patrol), while a further two Sea Furies escorted a helicopter en-route for the downed pilots location. After a tense 38 minutes, the pilot, severely injured, was rescued. He was treated on HMS Manchester. Further sucessful strikes were launched, involving numerous attacks on North Korean targets and an incident in which an aircraft from Theseus was shot down, in which the downed pilot, Lieutenant Bowman, was rescued by the helicopter pilot Lieutenant Roger Gill, who was later awarded the DSC (Distinguished Service Cross) for a courageous rescue, that involved heavy small arms fire from enemy soldiers at the British Consul in Seattle.
On the 15th January, the combined Commonwealth/US task force operations came to an end with the departure of the American carrier USS Bataan. Theseus herself continued operations this time on the west coast of Korea. On the 17th January Lieutenant Hamilton ditched his aircraft 60 miles from Theseus, spending about 55 minutes in very choppy waters until being rescued. Two days later operations from HMS Theseus came to an end after an astonishing and brave series of patrols, that at times culminated in tragedy. Theseus toured the harbour of Sasebo, before passing through the boom. The crews of the carriers Unicorn and Glory, the latter her replacement for the patrols that she had undertook, and of the same class as her, manned the sides, cheering Theseus on as she departed, Theseus herself doing the same. During the Korean War, six Commonwealth carriers operated throughout the conflict, five from the Royal Navy and one from the Royal Australian Navy, each performing whatever duty they were given to them with courage and professionalism.
In 1956 Theseus was used as an emergency commando carrier, along with her sister-ship HMS Ocean (1945) during the Suez operations from November to December. Helicopters from Theseus transported troops ashore as well as wounded soldiers back to Theseus. Compared to her actions during the Korean War, her role in the Suez Operations were relatively quiet. The following year she was placed in reserve. In 1962 a releatively brief, but eventful career truly came to an end when she was broken up at Inverkeithing.
Colossus Class Statistics