You’re disabled under the Equality Act 2010 if you have a physical or mental impairment that has a ‘substantial’ and ‘long-term’ negative effect on your ability to do normal daily activities.
What ‘substantial’ and ‘long-term’ mean
‘substantial’ is more than minor or trivial, eg it takes much longer than it usually would to complete a daily task like getting dressed
‘long-term’ means 12 months or more, eg a breathing condition that develops as a result of a lung infection
There are special rules about recurring or fluctuating conditions, eg arthritis.
A progressive condition is one that gets worse over time. People with progressive conditions can be classed as disabled.
However, you automatically meet the disability definition under the Equality Act 2010 from the day you’re diagnosed with HIV infection, cancer or multiple sclerosis.
What isn’t counted as a disability
There’s guidance on conditions that aren’t covered by the disability definition, eg addiction to non–prescribed drugs or alcohol.