One of the key aims of the Equality Act 2010 was to harmonise discrimination law that was previously segregated. They are all now contained in s.4 as ‘protected characteristics’ i.e. grounds on which discrimination will be unlawful. These are as follows:

Age
Disability
Gender reassignment
Marriage and Civil Partnership
Pregnancy and Maternity
Race
Religion or Belief
Sex
Sexual Orientation

You must avoid direct discrimination and indirect discrimination. In order to justify most discrimination the employer must show that its actions were a proportionate means of achieving a legitamate aim. What is "proportionate" and what is a "legitamate aim" can the principle of "costs" alone justify an act of discrimination? What "reasonable adjustments" would you have to make in respect of a person with a disability? Employers may fall foul of discrimination law and whether they intended to or not will be irrelevant.

“The intention or motive of the defendant to discriminate… is not a necessary condition to liability; it is perfectly possible to envisage cases where the defendant had not such motive, and yet did in fact discriminate....”

Lord Goff
R v Birmingham County Council, ex p EOC

The law surrounding discrimination can be complex and employers should take care and note that there is no statutory ceiling as to the amount of compensation that can be awarded.