Police are now hunting three men, all of them black, who are believed to have fled the scene in a blue vehicle.
A spokesman for Northamptonshire Police said: "At about 4.10pm, we received a report of an altercation in St James Park Road, which resulted in a man suffering serious injuries and being taken by ambulance to Northampton General Hospital."
The 38-year-old Byrne, head coach at Northampton Amateur Boxing Club, is no stranger to brushes with the law. Only last month, he was made subject of a restraining order requiring him to keep away from ex-girlfriend Gabrielle Reeves for 10 years after he harrassed and assaulted her on several occasions.
He was also ordered to attend a community rehabilitation programme involving courses in anger management and drug avoidance.
Byrne, who was undefeated as a pro in the 90's, was once convicted of breaking his best-man's jaw.
http://www.boxrec.com/boxer_display.php?boxer_id=027415
