Channel 4's 'Diana: In Her Own Words' gave the British broadcaster its biggest documentary audience in more than three years.

Prince Diana

Prince Diana

The controversial show was the source of much intrigue prior to its airing and the conversation surrounding its content appears to have boosted its viewing figures, with as many as 3.5 million people tuning in to watch it.

Overnight ratings confirmed the popularity of the documentary - which featured private video recordings in which Princess Diana spoke about her life with Prince Charles - but it was still bettered by the series finale of the BBC One period drama 'Poldark', which attracted an average of 4.9 million viewers.

In the documentary, Princess Diana opened up about her "greatest love" - but didn't reveal the identity of the unnamed man.

The Princess - who died in a car accident in Paris, France, in August 1997 - said: "When I was 24 or 25 I was deeply in love with someone who worked in this environment [security].

"But then he was chucked out and he was killed."

Although the Princess didn't name the man, it is thought she was talking about her former bodyguard Barry Mannakee, who died aged 39 in a motorbike crash in May 1987 while he was on his way home to Loughton, Essex, south east England.

She said: "Eventually he had to go and then three weeks after he left he was killed in a motorbike accident.

"He was the greatest love I've ever had, and that was a real killer."