Mr Brilliant says he was “horrified” when he first heard the allegations that Al Fayed had abused hundreds of women and says he “beat himself up” about whether there was anything he should have questioned more.
He told the BBC about surveillance, sackings, and a culture designed to keep top managers from trusting or communicating with one another.
This made it harder for them to do their duty as directors to exercise independent judgement and check Al Fayed’s power – or ask questions which may have revealed more to them about how he was treating women.
“I 100% can see how the management structure and culture was set up to cover it up, mask it from people,” says Mr Brilliant.
Four other former directors have anonymously confirmed elements of this picture.
A US citizen, Mr Brilliant was 36 when he joined the firm in August 2000. He was hired to relaunch the Harrods online business.
He says that shortly before his first business trip to visit Microsoft in Seattle, Al Fayed gave him a brown envelope containing $5,000 (£3,993) in $50 notes.
After the trip he tried to return the full amount. He says Al Fayed refused, asking him, “You didn’t need any entertainment?”
Mr Brilliant replied that he did not need it – he had been too busy to visit the cinema or theatre, and someone else had paid for dinner.