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 potting shed in County Durham and Britain's first ever bird research station in Northumberland.

BBC: NEWS | UK | England | Cumbria | Lotto cash saves endangered tower

Run by full-time chairman Richard Tims, 43, the oldest football team in the world has gone from its humble beginnings in a Sheffield potting shed to a club of three senior teams, 13 junior teams, a women's team and one disability team.

BBC: Potting shed birth of oldest team

Their productivity may decline as they get older although people gain in experience, their capacity for sharp thinking falls off but the traditional pattern of retirement, in which one day an employee is in a bustling office busy as a bee and the next he is good only for the potting shed and the fireside chair does not make sense for the economy, for companies or for people.

ECONOMIST: Older workers