The Equality Act 2010 includes "religion or belief" as protected characteristics, where the "or belief" part is defined in section 10(2):
Belief means any religious or philosophical belief and a reference to belief includes a reference to a lack of belief.
So there is no categorical protection for other kinds of beliefs, including political beliefs. However, currently the law is interpreted to mean that some political views do amount to philosophical beliefs, and that others can be protected if they are "based on" or "manifestations of" religious or philosophical beliefs.
In Mr C McEleny v Ministry of Defence: 4105347/2017, the court found the claimant's belief in Scottish independence to be a protected philosophical belief. The claimant even quoted from the Scottish National Party's manifesto, so it was certainly a political view; but the Employment Tribunal found that it amounted to a philosophical belief for the claimant, based on the five-part Grainger test:
(i) The belief must be genuinely held.
(ii) It must be a belief and not an opinion or viewpoint based on the present state of information available.
(iii) It must be a belief as to a weighty and substantial aspect of human life and behaviour.
(iv) It must attain a certain level of cogency, seriousness, cohesion and importance.
(v) It must be worthy of respect in a democratic society, be not incompatible with human dignity and not conflict with the fundamental rights of others.
Note that the Grainger test concerns not just what the belief is, but also why the person believes it. Particularly, a political view believed because of evidence rather than ideology would fail point (ii).
Also, in Dr David Mackereth v The Department of Work and Pensions (1) Advanced Personnel Management Group (UK) Limited (2):  EAT 99 the Employment Appeal Tribunal found that the claimant's disbeliefs that
(i) a person can change sex/gender, (ii) that “impersonating” the opposite sex may be beneficial for a person’s welfare, or (iii) that society should accommodate/encourage such “impersonation”
were protected because "they are based on the claimant’s belief (a) in Genesis 1:27" and are "manifestations of that belief". The third of these listed disbeliefs directly concerns a matter of public policy, and I think most people would recognise it, in isolation, as a political view.
So the effect of recent rulings along these lines seems to be that if a company were to post a job advertisement which banned applicants who held a certain political view, then that company would be open to a successful challenge under the Equality Act 2010 by any prospective applicant who held that political view but could successfully show either that
- For themselves it amounts to a philosophical belief, or
- For themselves it is "based on" or "a manifestation of" a religious or philosophical belief.