For the next six to eight weeks steeplejacks will be carrying out essential work on the 180ft chimney at Salts Mill.

To keep out rainwater, a galvanised steel plug is being inserted about a metre down inside the mouth of the chimney which dates back to 1853.

That is when the mill, designed by Lockwood and Mawson, the men who designed the landmark City Hall and St George’s Hall buildings in Bradford, was opened by wool magnate Titus Salt on his 50th birthday.

Up to six men from Access Steeplejacks in Leeds are busy setting up ladders and netting to replace lightning conductors at the top of the chimney.

A Salts Mill spokesman said the work, which also includes some repointing of the Yorkshire Stone brickwork near the top, is likely to cost a five-figure sum.