Barry's Cold Knap Lido was opened on 1 May 1926 and was constructed by the voluntary labour of the local unemployed. Once one of the largest open-air swimming baths in Britain, it measured 120 yards by 20 yards. The lido's original form was much simpler than that which survived into the early 2000s. In common with many open-air swimming baths constructed by voluntary labour in the 1920s and 1930s, it was flanked by wooden changing boxes rather than the concrete, semi-circular ones that can be seen in Royal Commission Aerial Reconnaissance. These were situated along the western edge (that closest to the boating lake) and also ran for about 60 yards along the length of the swimming pool. Aerial photography taken by the Aerofilms company in 1929 (along with the 4th Series 25'' O/S mapping of c.1936) confirms the simple design of the baths in their earliest years. The semi-circular changing boxes familiar to post-war swimmers were built in c.1937 and are present on the 4th Series 6'' O/S mapping of c.1938. Later additions to the site include the post-war children's paddling pool shown on the 5th series 25'' O/S mapping of c.1955. Enjoying its heyday in the 1950s, Cold Knap fell into decline in the 1980s along with many other open-air swimming baths across Wales and was eventually closed in 1996. Despite local opposition, demolition of the buildings and infilling of the pool commenced in March 2004 and the site has now been landscaped with pathways that layout the original imprint of the baths.

Daryl Leeworthy, RCAHMW, 30 January 2012.