The British National Party faces a data protection probe after its entire membership list was posted online.
The list includes the names, addresses, phone numbers and email addresses of all members up to this September.
The list also include some people's ages, including those who are only teenagers. In addition to standard personal details, there are also details of members' jobs.
As the BNP list includes members who are in the forces, police officers, prison officers, teachers and nurses, some individuals may face the sack.
It is illegal for forces personnel and police officers to be members of a political party. Others are in roles where membership of the BNP may be frowned upon by their employers.