Though he's taken pictures of drug wars and hardship around the world, British photographer Nick Stern couldn't handle snapping Britney Spears. Stern resigned from Splash, a celeb photo agency, after becoming horrified by the ruthless, unsafe means used to pursue the tormented pop singer/mental-ward patient.

Stern spoke with Radar from Mexico, where he's taking a few days off following his resignation. Asked if there was a specific moment that lead him to resign, Stern recalled one particularly horrific moment when a gang of paps, 20 to 30 deep by his measure, pursued Britney as she exited a pharmacy. Walking backwards and snapping photos, the mob trampled a homeless woman without bothering to help her. "I'm absolutely dismayed and horrified at the spectacle in front of the general public."

"Britney herself is clearly very ill," Stern added. "Anybody who cannot see that girl needs help is blind or stupid. If you look at the way in which her behavior has descended, you have to also consider where it will end. She's not going to suddenly wake up tomorrow fine."

Stern's covered Britney for Splash since August 2007, but by early January, on ethical grounds, he requested not to be sent on any further Spears assignments. Splash disregarded the request and sent him to snap Britney at her custody hearings, and last Saturday he e-mailed his resignation.

While Stern says he initially thought the move could be "seriously detrimental to his career," it's had the opposite effect. He's received dozens of phone calls and e-mails of support from colleagues—and the occasional job offer. He's now making a documentary about Brit's relationship to the press for Britain's Sky TV. "The story isn't Britney. The media surrounding her is now the story," he says.

Two years ago, Stern himself made headline news when he was sued by the David and Victoria Beckham for breach of privacy for aerial shots he took of their garden. The case ended in a £6,000 fine for Stern, with legal expenses for both parties falling to the Beckhams. Stern viewed the case as retaliation, as the shots captured some unauthorized backyard construction that got the Beckhams in trouble with authorities.

Reached for comment, Splash told Radar that they had "no comment."