Can an employer defend a direct discrimination claim on the basis that any discrimination was unintentional?

In order to prove direct discrimination a claimant must show that the employer has treated him or her less favourably because of a protected characteristic (eg sex, race or sexual orientation) than the employer treats or would treat other persons in similar circumstances. If the claimant can prove this, the motive behind the employer's action or its lack of intention to discriminate will be irrelevant.