Where an unsuccessful job applicant asks for details of why they were not offered the job is the employer obliged to provide these?

There is no duty in law for an employer to inform an unsuccessful job applicant why they were not selected for the post applied for, even if the applicant makes such a request. Many employers do, however, provide feedback on this in order to be helpful.

Job applicants do, however, have the right under the UK General Data Protection Regulation (retained from EU Regulation 2016/679 EU) (UK GDPR) to submit a request for access to any information held about them by the employer, provided that the information is held either in a structured manual filing system or on computer. This is known as a subject access request. On receipt of a valid subject access request, the employer must give the applicant a copy of all the personal data it holds about them (with the exception of documents that, if disclosed, would reveal personal information about another person). It follows that if there is written documentation about the reason for not offering the individual the job on file, a copy of that document would have to be disclosed to the individual. There is, however, no duty under the UK GDPR to disclose information that is not recorded, ie there is no duty to create documents for that purpose.