He won't be able to because anyone employing such a technique generally wouldn't be stupid enough to use those exact terms.
There are plenty of examples in the UK, specifically with the BBC, putting out recruitment campaigns that specifically state they only take in Black/Minority candidates. There is no reason for it other than to boost 'diversity'. The jobs are just as capable of being done by black people as any other colour.
This is highly unlikely, if only because such hiring practices would be unlawful in Britain in almost all cases.
You can use diversity as a tie-breaker, and you can actively try to persuade people from various under-represented groups to apply, but you can't specifically state that you only take Black candidates (source: https://assets.publishing.service.gov.uk/government/uploads/...)
The BBC is a large centralised organisation with a hefty HR team and a lot of people who like to beat on it. They're the last people I would expect to be advertising illegal hiring practices.
There are plenty of examples in the UK, specifically with the BBC, putting out recruitment campaigns that specifically state they only take in Black/Minority candidates. There is no reason for it other than to boost 'diversity'. The jobs are just as capable of being done by black people as any other colour.