Under the Equality Act, an employee is disabled if they have a physical or mental impairment that has a substantial and long-term adverse effect on their ability to carry out normal day to day activities. Historically, a "normal day to day activity" was interpreted as an activity that was normal for a large group of people; it did not focus on what was normal for the individual employee. This meant that an activity that was relatively job-specific – such as lifting heavy items – would not necessarily be a "normal day to day activity". That approach has now been overtaken by EU case law, as demonstrated in the EAT case Banaszczyk v Booker Limited.

As a "picker" in a warehouse, the employee had to lift packages weighing up to 25kg at a rate of 210 packages per hour. After he sustained a back injury in a car accident, he was no longer able to reach the required picking rate and he was ultimately dismissed.

The employment tribunal found that the employee was not disabled under the Equality Act. It focused on the activities outside work that the employee was still able to do – such as the shopping – and concluded that the back injury did not have a substantial adverse effect on his ability to carry out normal day to day activities.

On appeal, the EAT overturned the decision and pointed out that the employment tribunal had not taken full account of EU cases that focus on whether an impairment hinders an employee's participation in working life. Normal day to day activities include the skills required for work. Here the employee's role required him to lift and move goods weighing up to 25kg; this amounted to a normal day to day activity, both for the employee and for many others working in warehousing and distribution. The employee's back injury meant that he was unable to lift and move packages as quickly as would otherwise have been the case and as such had a substantial adverse effect on his ability to carry out normal day to day activities. Accordingly he was disabled and could proceed with his disability discrimination claim.