Does an unsuccessful job applicant require concrete evidence to prove that they were discriminated against?

Because employment tribunals work to the "balance of probabilities" test, they do not require an applicant to provide proof beyond reasonable doubt that they suffered discrimination. If the applicant can prove facts from which the tribunal could conclude that the employer has committed unlawful discrimination, the burden of proof shifts to the employer to provide a satisfactory, non-discriminatory explanation. For example if a female applicant who is rejected for a position can show that a male candidate was appointed who was less suitable for the job in terms of qualifications, experience and skills, on the face of it, it could be concluded that they have been discriminated against on the ground of their sex. The employer will have to show that it had a non-discriminatory reason for selecting the male candidate.