You have the right to the same treatment as someone in a heterosexual relationship who is not married - this includes pensions benefits.
However, if the benefit is explicitly restricted to married partners, the employer will be able to exclude you without breaking the law (ie. provided that the benefits in question are also denied to unmarried heterosexual partners). In other words, it remains legal to discriminate against people who are not married or in civil partnerships, but it is unlawful to discriminate against someone on the grounds of their sexuality.
Same sex couples who register their relationship formally have the same legal rights as married opposite-sex couples under the Civil Partnership Act 2004. The legislation covers hospital visiting rights, next-of-kin rights and a very important right for a surviving partner to benefit from a dead person’s occupational pension schemes on the same terms as a widow or widower. This right has been backdated to 1988.
