Batley and Spen By-election Discussion

On July 1st there will be a by-election held in the Batley and Spen constituency in West Yorkshire. This contest offers the latest potential blow to the Labour party; either at the hands of the Tories or else potentially even the Workers Party, whose candidate and leader George Galloway previously upset Labour under similar circumstances in Bradford West a few miles away in 2012.

What are the potential implications of Labour losing this seat under either scenario? What kind of impact could it have over national politics?