The former Libertines frontman was arrested after an incident at the Rookery Hotel in Clerkenwell on Wednesday evening. A second musician was arrested hours later at the hotel. Max Carlish, a film-maker who has spent seven months making a documentary on Doherty's new band, Babyshambles, said he was attacked by the singer and needed hospital treatment for two black eyes and a broken nose.
Doherty, who was kicked out of The Libertines after failing to curb his self-confessed addictions to heroin and crack cocaine, accused Mr Carlish of selling pictures to newspapers apparently showing the musician smoking heroin, according to reports. Mr Carlish later claimed the move was designed to shock the singer into rehab.
Mr Carlish told the Daily Mirror: "I was in a hotel with Pete and everything was going fine until he started demanding loads of cash. He wanted thousands and I knew he was going to go out and spend it on heroin. He was desperate for a fix. I said `no' and he went berserk, punching me. There was nothing I could do.
"Despite the drugs he's quite a big bloke. His eyes were wild. It was terrifying. He beat me and he wouldn't stop. My face is a mess. He stole all the money I had and my mobile phone."
Mr Carlish, 38, later added that he would not be pressing charges as he didn't want to hear about his friend "hanging on the end of a rope in a jail cell somewhere" and offered to pay for him to go into rehab.
A Scotland Yard spokesman said that officers were called to a hotel in Peters Lane, London EC1, at 6.20pm following a report of a man being assaulted.
The spokesman said: "A 25-year-old man was arrested on suspicion of assault occasioning actual bodily harm and theft. He was taken to a north London police station and remains in custody." He added that a man in his thirties was taken to University College Hospital with facial injuries, but was understood to have been discharged.
Doherty, 25, has been a focus of tabloid interest since he was linked a few weeks ago to the 31-year-old model Kate Moss.
In the past Doherty has claimed to have spent pounds 1,000 a day to feed his drug habits. He was jailed for six months for burgling the house of a Libertines bandmate, Carl Barat, in 2003, and in September last year he received a four-month suspended sentence for possessing a flick knife.
In a interview with the Mirror published yesterday, he spoke of his plans to go into a drug rehabilitation centre in west London on Monday.
Doherty's band, which has earned critical acclaim and chalked up a top- 10 hit with "Killamangiro", will go head-to-head with The Libertines later this month at the NME Awards for the title of Best Live Band.