Ed Sheeran's manager on royal duels, Russell Crowe's snakes and a secret new album

Stuart Camp and Ed Sheeran might have the most eccentric working relationship the music business has ever seen – the pair even have their own fanart and many a joint fanpage.

For instance, as Camp told my UK music podcast Straight Up (co-hosted with Kathleen Johnston), the musician insists on updating their management contract annually with one curious new clause. So far, these include 47-year-old Camp keeping pictures of the Weasley twins from Harry Potter in his wallet pocket, always eating a Colin the Caterpillar cake on his birthday, and always smiling in Sheeran's presence.

"I remember it started when we were in Japan or Korea," Camp, who hasn't yet breached a single clause, told me.

"We were in a Chinese restaurant. And he was very drunk and being really, really obnoxious. So I refused to sit next to him. I said, "I'm not sitting next to you being an asshole." And I think it was just the time we were negotiating the contracts and so he instantly rang his lawyer at the table and said, 'You need to put a clause in his contract, he has to sit next to me at all times.' And then it all went from there..."

Camp, whose first job was at a chicken processing plant before he cut his teeth managing James Blunt, Lily Allen and The Darkness, first met Sheeran at a West London pub in 2009, just as the star was being dropped from his previous management. "They said he wasn't going anywhere. They wanted him to drop the looping and dye his hair black and give up rapping," Camp said. The pair began working – and living – together a year later, and Camp reportedly now earns $13m a year. "But for a long time the previous management's website even said they discovered Ed Sheeran!" Camp added.

The day after Camp became Sheeran's manager, Sheeran turned up on his doorstep, and refused to leave. "We moved house three times. I moved to a house with only one bedroom he still managed to come!" Camp told the podcast. "Eventually my girlfriend and I sort of talked him into buying a flat and he bought he bought the flat opposite me. My girlfriend asked me, 'Do we need to feed him?' Then the first night, we opened the curtains of our flat and looked over the road. And he was just standing at his window staring at us. So we moved again to Balham, and he bought the f______ flat above us!"

Camp's work as manager to the world's most successful male recording artist is no walk in the park. He hasn't had a holiday since 2001, "unless you count the time I went to Antarctica...with Ed," he said. When Sheeran goes on holiday, Camp is always phone in hand, primed for disaster. There was the time the star melted the skin off his foot in a boiling spring up a mountain, for instance, requiring a skin graft, as well as a near-death experience while staying at Russell Crowe's house in Australia.

"We'd gone to his farm, the oldest, most beautiful thousand-acre farm in northeast Australia," Camp said. "And he had a pub in his garden, which is where Ed got the idea of putting a pub in his own garden. And Russell had brought back to his house the local soccer team, like the local girls soccer team. Some other random actors were there, Ed's security guard Kevin and Ed, and everyone was getting really, really drunk.

"And then I think towards the end, we discovered there was a full-size arcade underneath this pub. And we were playing, while Ed wandered off to find our cabin across this bloody field that we were told not to walk in, because of the snakes, and because you could die. So there's people chasing him on on bikes, and then we find him, asleep in the field. I suppose he had that drunk homing pigeon instinct..."

Another hair-raising call was from the Palace, after Sheeran, while partying at the Royal Lodge of Windsor (home to Prince Andrew) with James Blunt and Princess Beatrice, got into an accident, according to tabloids at the time. Princess Beatrice was reported to have taken a ceremonial sword from the wall in an attempt to knight Blunt in jest, and mistakenly sliced Sheeran's cheek. Sheeran, who never publicly named the Princess, required stitches.

"I got quite protective over that," said Camp. "Because we've never publicly commented on it. But certain people said, 'Oh, you should lie and say it wasn't her and say it was someone else.' I said, well, we're not telling anyone anything. I'm not lying, just because someone's a f______ idiot. Because they're thinking, yeah, I will get paralytic and take a sword off the wall. You're just asking for trouble. You know, we've not heard hide nor hair from her since."

Sheeran is currently on a break after his girlfriend Cherry gave birth to a baby girl, but Camp has revealed a new album is in the works. "He has everything planned out. I'm actually looking up at a piece of paper on which he has written the tracklist for the album after the next one."

Listen to Straight Up, available on wherever you get your podcasts, to hear more about the strange and secret life of Stuart Camp and Ed Sheeran