(17 May 2015, 9:19 pm)aureolin wrote The main ones are Unison, Unite, GMB and the CWU. There's also the likes of BECTU, USDAW and the NUM. The PCS has been politically neutral for as I can remember.
TUSC is heavily supported by the RMT and I'm sure Bob Crow had something to do with it's creation.
According to the Wikipedia page of the TUSC, leading members of the PCS are on the steering committee alongside the RMT, NUT, the Fire Brigades Union and the Prison Officers Union. Not that neutral as it turns out.