Leeds bricklayer Joseph Aspdin patented the cement formula in 1824 and called it Portland Cement because it resembled Portland stone when hardened.

Weardale limestone and shale were quarried 450ft above the works, crushed and ground to powder before passing down a 900-yard enclosed conveyor.

Blue Circle cement was used in the Newcastle's Millennium Eye, the Stadium of Light and the Nissan car factory, at Sunderland.

Eastgate's 72 residents have not cleaned their own windows for 30 years. The plant employs contractors to do the job, even though the original "grey dust" was reduced by new technology.

A local publican lost a catering contract because he used the works ovens to cook beef for his own customers.

Vanishing wellies worried bosses when they found that more were being issued than there were workers on the payroll. One manager asked: "Are all the sheep in Weardale wandering round in yellow wellies?"

Rooks vanished from Eastgate when the plant was built and stayed away for two years but, according to Durham Bird Club, they shouldn't be disturbed when the plant is demolished.

The works had its own eel farm in the early 1980s. Eels flourished in recycled warm water and were exported to Holland where they were smoked and considered a delicacy.