The organisation says those at risk range from a 1920s chemical silo in Billingham and lime kilns at South Shields, to a greenhouse with a pottingshed in County Durham and Britain's first ever bird research station in Northumberland.
Run by full-time chairman Richard Tims, 43, the oldest football team in the world has gone from its humble beginnings in a Sheffield pottingshed to a club of three senior teams, 13 junior teams, a women's team and one disability team.