Is someone with HIV, cancer or multiple sclerosis protected under the disability provisions of the Equality Act 2010 only at the point that the condition affects his or her ability to carry out day-to-day activities?

No. Under para.6 of sch.1 to the Equality Act 2010, people diagnosed with the progressive conditions of HIV infection, multiple sclerosis and cancer are deemed to be disabled whether or not the condition has yet begun to have any effect on their ability to carry out day-to-day activities. The rationale behind this is that these diseases can stigmatise sufferers from the point of diagnosis, as well as having a huge personal effect on them.