It was still hot in the summer and cold in the winter when I started at Trewins in 1984. When it was really hot, permission had to be given by the MD before men could remove their jackets and ladies allowed to go bare legged (no tights!)

Mr. Yelland (Service Manager) at 11am each day used to go onto the roof of the main building with a "whirling hydrometer", (which looked like a football supporters rattle.)  This was used to measure the temperature and humidity.  If it reached the required temperature the men were permitted to remove their jackets and the ladies  their stockings or tights, allowing a little personal comfort.