Wife recently read out a job application in ( social care area) which asked if she had stood for or voted for BNP....she hadnt / hasnt but we were kind of annoyed at that potentially removing her as a candidate for the job. ( applicants submitting yes here were not required to complete application)
Intrestingly enough also the question only related to BNP and not any other religious / fundamentalist / extremist groups or parties

The idea that kind of question might (legally/morally) be asked or indeed made stipulate on a job description is dumbfounding!

There are certainly provisions for the protection of the 'vulnerable' on the basis of CRB or registration on the S.O register etc.....however standing on behalf-of, voting-for or simply having a leaning towards an 'official' (registered/recognised) British political party cannot be good-enough reason to proscribe anyone from applying for an advertised vacancy.
I bet such a stipulation wouldn`t stand up in a light breeze; let alone an employment tribunal.
