HIV is listed as a protected characteristic under the Equalities Act 2010. This means that it is unlawful to discriminate against anyone for their HIV status.
Disclosure and relationships
You do not have to tell your partner or someone you have sex with that you have HIV as long as you take appropriate precautions. These precautions may differ due to personal circumstances and also what you have been advised by health professionals, but they may include taking HIV medication regularly to ensure you have a fully-suppressed viral load or using condoms and lubricant with you partners.
If you do not take precautions and do not disclose then you could be charged with a criminal offence if HIV is transmitted to your sexual partner. The law is slightly different still in Scotland where you can be prosecuted for risk of transmission.
Disclosure and work
Under the Equality Act 2010 it is unlawful to discriminate against anyone for their HIV status.
Employers are not allowed to ask whether or not you have HIV at the begin of any recruitment process. There are some occasions when they are allowed to ask you once you have been offered the job. It is illegal for an employer to rescind their offer of employment if you disclose your status.
There are a few exceptions to this rule. The army does not take applications from people who are HIV+, but this is the same for many other long-term health conditions. Some health-care professionals must know their HIV status, although these are usually roles where there could be blood on tissue contact, such as midwifery or surgery. There are restrictions on HIV+ pilots and air traffic controllers.
Further information about HIV and the law
Unfortunately, discrimination still occurs. Employers are still requesting HIV status of their employees, dentists are still asking before people have procedures done. National Aids Trust (or NAT, for short) have some really good resources on HIV and the law. Why not check some out here?