throughout the first decade of the 20th century, the population of the borough of todmorden remained constant. the ten-yearly uk census returns show figures of 25,418 in 1901 and 25,404 in 1911. like the rest of the upper calder valley, todmorden's economy experienced a slow decline from around the end of the first world war onwards, accelerating after the second world war until around the late 1970s. during this period there was a painful restructuring of the local economy with the closure of mills and the demise of heavy industry.