The deal was unusual enough to be worth remembering. With Britain at war in 1940, the Admiralty had already requisitioned Butlin's flagship camp at Filey in Yorkshire for naval training and now wanted two more: one in north Wales, one in Scotland. They asked Butlin himself to build them. Butlin agreed, on condition the camps reverted to him after the war, and went hunting for land on the Llyn. He found his hundred and fifty acres near Penychain station on the Cambrian Coast line. The camp opened as HMS Glendower in 1940, an overflow training base for HMS Royal Arthur, the navy's name for the requisitioned Butlin's Skegness. It was extended in 1942. When the war ended Butlin took it back, refitted it for civilian use, and opened it to the paying public in 1947.

Everything that defined Butlin's was here. Indoor and outdoor swimming pools. A boating lake. Tennis courts. A ballroom. A miniature railway and a chairlift carrying campers above the chalets between attractions. The dining hall with its long tables, the morning wake-up call over the speakers, the sports field for the three-legged race and the egg-and-spoon and the donkey derby. Redcoats moved through it all like cheerful sheepdogs, organising and entertaining and keeping the timetable moving. A chapel served Catholic clergy on subsidised holidays; on Sunday mornings a non-denominational service filled the main theatre in the Gaiety Building. In 1962 that building was rebuilt as a million-pound entertainment complex. In the early hours of 9 August 1973 it burned to the ground. Faulty electrical wiring, the investigators ruled. No one died, though some campers suffered minor injuries from smoke and broken glass.

On 9 August 1963, ten years almost to the day before the Gaiety fire, Queen Elizabeth II and the Duke of Edinburgh paid an official visit to the camp. The Redcoats turned out in formation; the campers, on holiday in their summer best, lined the paths and waved. The visit became part of the camp's institutional folklore, photographed and rephotographed in every promotional brochure for years afterwards. Less welcome was the summer of 1989, when a tornado tore through the chalet lines mid-season and forced the evacuation of three thousand five hundred guests. The repair bill ran to about two million pounds and helped tip the camp's parent group toward a rebrand.

The 1987 rename to Pwllheli Holiday World was followed by Starcoast World in 1990, both attempts to refresh the brand as Butlin's reputation faded against the new lure of cheap Mediterranean package holidays. In 1999 the camp was transferred within The Rank Group to its Haven Holidays subsidiary, and the following year both Butlin's and Haven were sold to Bourne Leisure. Haven gave the site a Welsh name, Hafan y Mor, meaning Sea Haven, and stripped out most of what had defined the Butlin's era: the chairlift came down, the miniature railway was lifted, the roller coaster and the funfair vanished. The chalets gave way to static caravans. The camp is still there, busy each summer, but the institution that opened in 1947 belongs now to memory, to grandparents' photo albums, and to the small Penychain halt where trains still call by request for anyone heading to the holiday park's gate.