Home Secretary Jack Straw won a majority of 14,451 at the last election - the healthiest of his parliamentary career - but this seat has not normally tended to deliver monolithic Labour support.
In 1993, for example, Mr Straw's majority was only 3,000 though he increased this to 6,000 in 1992.
Blackburn is by and large a working-class constituency. One in five people are non-white, predominantly Asian, and mostly concentrated in the terraces found in the town’s centre.
Blackburn used to be the weaving centre of the world but textiles form a far smaller proportion of the town’s manufacturing output nowadays, which has led to local unrest over the decline of traditional industries. Modern-day businesses are to be found in the manufacturing, engineering and distribution sectors, and the area is a brewing centre for a large part of the north.