Pete Doherty says he once used another man’s urine to fool drug testers.

‘I was banging it,’ he says. ‘The only time I tested clean was when I used someone else’s piss.’

But the singer, who showed off a drug-free certificate as he left jail last week, denies taking hard drugs inside.

‘There are ways of getting gear in, but how do you get a syringe in?’ he explains.

‘I was in segregation for the last 3 weeks. Supposedly I was in debt to big-time drug dealers.

‘All I’ll say to that is: Chance would be a fine thing.’

Pete, 29, also claims fellow lags threatened to stab him over his relationship with Kate Moss, 34.

‘Everyone was on me – not physically, just general attention,’ he tells NME.

‘It was quite hard work. Constant shouting: “Pete, is Kate Moss a good sh*g? Give us a song.”

‘There was this one bloke convinced I had been ignoring him because he’d been shouting my name over and over. But I’d been asleep.

‘I woke up to hear: “You wait, I’m going to see you outside and stab you up.” It was f***ing terrifying.

‘I didn’t know whether to keep my chin up or my head down.’

Pete, who says drugs once caused him to attempt to batter his kitten with a spade, was released from Wormwood Scrubs Prison after serving just 29 days of his 14-week sentence.