There is no legal requirement for members of an interview panel to receive training, but anyone on a recruitment panel needs to understand how to make a good decision that is transparent and fair, and based only on factors that are relevant to the job for which your employer is recruiting.
In particular, every panel member will need a good knowledge of the law concerned with discrimination.
The recruitment process is one of the most likely places where discrimination can take place at work. If an unsuccessful candidate challenges your employer at a tribunal, your employer will need to show that it operated fair procedures. An employer that fails to train its recruiters adequately is more likely to be found to have broken equality laws.
If you are not offered formal training, you should ask for a briefing on how your organisation ensures that equal opportunities apply to recruitment.
Members of a recruitment panel can find themselves personally liable alongside their employer for a discriminatory recruitment decision, so knowing how to make a non-discriminatory decision – and also how to be able to demonstrate to any unsuccessful candidate the basis for that decision if challenged – is also important for your own protection.
The Equality and Human Rights Commission website has lots of good practical guidance for employers on avoiding discrimination during recruitment.
As well as issues relating to the protected characteristics under the Equality Act, which are age, disability, gender reassignment, marriage and civil partnership, pregnancy and maternity, race, religion or belief, sex or gender and sexual orientation, your training should cover other areas such as the need to avoid trade union victimisation or blacklisting, and how the law requires you to approach criminal convictions.
It is also unlawful to decide not to employ somebody because you know they 'blew the whistle' on their previous employer.