If you are HIV+ you are covered by the Disability Discrimination Act 1995. However your employer would need to know about your HIV (and any other conditions) in order to realize it has extended duties to you under this act.

The act lays down in law. Certain additional duties such as allowing you time off for medical appointments. Importantly is introduces a process called "reasonable adjustments".

For example. If you have mobility problems and you work in an office up several flights of stairs. You might request a "reasonable adjustment" to your work environment. That allows you to work in an office on the ground floor.

Your employer than has to provide such an adjustment if the costs of doing so are not prohibitive.

You may need to reduce your hours. Again if medical evidence supports this. You might make a request for a "reasonable adjustment" to your working hours. Though please be aware that your employer may decide to reduce your salary, quite legally, pro rata.

If you are in a trade union. They will be able to advise you on this. Some HIV support services and/or your legal representatives will be able to advise you on this in more detail.

The Act can be found at http://www.opsi.gov.uk/acts/acts1995/ukpga_19950050_en_1 & http://www.opsi.gov.uk/acts/acts2005/ukpga_20050013_en_1.htm

The governments website also has information to help you http://www.direct.gov.uk/en/DisabledPeople/RightsAndObligations/DisabilityRights/index.htm