BABYSHAMBLES star Doherty is said to have walked into Razorlight's dressing room just before midnight, where he headbutted Borrell before being escorted out by security guards.
Borrell then reportedly punched Doherty to the ground, before walking away.
An insider tells website NME.com, "Rumour is that Doherty walked into the band's dressing room last night after both bands had played and in an unprovoked attack headbutted Johnny Borrell.
"Johnny put Doherty on the floor and left the dressing room, at which point festival security escorted Doherty from the dressing room and back to his bus."
British newspaper The Sun reports Doherty as saying minutes after the fracas, "I've been staggering around trying to see a band. But I headbutted Johnny Borrell. So I've got to go really."
Borrell once played bass in an early incarnation of Doherty's previous band, The Libertines. He recently criticised Doherty's well-publicised struggles with crack cocaine and heroin, saying, "I look at someone like Peter and I think, 'You're a moron.'"