A pavilion was built for the 1951 Festival of Britain and occupied a large space in the southern half of the park, the area where formerly the fountain stood and where there is now a car park. Owing to post-war controls on building materials it was necessary to adapt a war surplus aeroplane hangar to provide the framework for it. The hangar was obtained from Stormy Down aerodrome near Pyle, Bridgend in late 1949. The cost of dismantling and transporting it was £3,400 and rebuilding it in Sophia Gardens was estimated to cost £40,000. The pavilion when completed seated approximately 2,500 people, and the final cost of construction was £80,000. The Cardiff City Engineer at the time, E.C. Roberts, gave an account of the building of the pavilion in an article published in Glamorgan Historian. The official opening was arranged for Friday 27th April 1951.
Subsequent to the Festival of Britain the pavilion was used for a variety of events and sporting occasions. One such event was a fashion show held in 1952, featured in the British Pathé Film - Fashion Show In Cardiff AKA Berketex Fashions. This short film clip shows the interior of the pavilion, along with shots taken outside in Sophia Gardens. It was also the venue in 1958 for the Empire and Commonwealth Games, held between July 18 and 26th, for boxing and wrestling matches as well as for the grand dance on the last day of the Games.
A heavy snow fall on the night of 9th January 1982 caused the roof of the pavilion to collapse, and the building was subsequently demolished. A car park now occupies this space.
Sources of information