How Reuters captured the photo of former Prince Andrew leaving custody

Slumped in the back seat of his Range Rover, a visibly shaken man once referred to as the "Playboy Prince" stares ahead of him as the car leaves Aylsham police station in Norfolk, England.

The photo, taken by Reuters photographer Phil Noble, went viral when it was published late on Thursday. It shows Andrew Mountbatten-Windsor, the younger brother of King Charles, after he was released from police custody following a day of questioning over allegations he sent confidential government documents to convicted sex offender Jeffrey Epstein.

When news that Mountbatten-Windsor had been arrested broke early on Thursday, Manchester-based Noble began the six-hour drive south to Norfolk.

Journalists knew the former prince had been arrested in Norfolk - the county that is home to the royal Sandringham estate where he resides. Since officers from Thames Valley Police - covering southeast England - were questioning him, there were potentially 20 or more police stations where he could have been held.

Following a tip, Noble headed to the police station in the historic market town of Aylsham.

Not much was going on, Noble said. There were a couple of other members of the media there, including Reuters video journalist Marissa Davison.

Six or seven hours went by. Darkness fell. Still, nothing was happening. It seemed like this was the wrong station - after all, it was well over an hour's drive from Mountbatten-Windsor's home.

The team of two Reuters journalists decided to book rooms at a hotel. Noble packed up and started heading down the road towards it.

Minutes later, he got a call from Davison. Mountbatten-Windsor's cars had arrived.

Noble raced back, just in time to see the two vehicles leaving, at high speed. The front car contained two police officers, so Noble aimed his camera and flash at the car behind.

He took six frames in all - two showed police, two were blank, one was out of focus. But one captured the unprecedented nature of the moment: for the first time in modern history, a senior royal was being treated as a common criminal.

The image was used extensively by media worldwide.

"You can plan and use your experience and know roughly what you need to do, but still everything needs to align," said Noble. "When you're doing car shots it's more luck than judgment."

He hadn't looked closely at the former prince's expression, the photographer added. He was just relieved it was him.

"It was a proper old school news day, a guy being arrested, who can we call, tracking him down," he said.

Mountbatten-Windsor, the second son of the late Queen Elizabeth, has always denied any wrongdoing in relation to Epstein, and has previously said he regrets their friendship. The current police investigation, which is not related to any allegation of sexual impropriety, involves the suspicion of committing misconduct in public office, according to a statement released on Thursday by Assistant Chief Constable Oliver Wright.

The former prince's office did not respond to a request for comment on Thursday. He has not spoken publicly since the release of millions of pages of documents by the US government relating to Epstein, who was convicted of soliciting prostitution from a minor in 2008.