A police worker from Lancashire was sacked after it was discovered the person was a member of the British National Party.
Bosses say the worker, who worked in the force's eastern division which covers the Ribble Valley, Longridge, Clitheroe and other parts of East Lancashire, had their contract terminated after a leaked copy of the party's membership list was published online in 2008. An investigation was launched after the worker, who has not been identified, appeared on the list.
The disclosure was covered in answer to a Freedom of Information request to the force.
Ribble Valley MP Nigel Evans said all political parties should be treated the same. He added: "I think the guidelines should affect everyone equally. As much as I might hate everything the BNP stands for, they are a legal party and have representation at local government level and European Parliament level and they do score a lot of votes out there."
It is not clear what post the worker had within the force.
The Freedom of Information request also revealed that no Lancashire officers were affiliated to the far-right party. A spokesman for Lancashire police said: "Membership or promotion of the BNP by any member of the police service, whether police officer or police staff, is prohibited as it conflicts with our duty to promote equality."
Association of Chief Police Officer guidelines adds that the policy "specifically includes the British National Party".
Lancashire Evening Post