A gang viciously assaulted a man as he walked through Wardown Park on Sunday evening.
The victim was walking along New Bedford Road towards the town centre, when he crossed into Wardown Park at around 7pm.
He was then set upon by the gang of men, who left him with serious injuries.
The gang were described as wearing dark clothing and fled the scene after the attack.
Det Con Paul Harris said: “This was a vicious and unprovoked attack which took place on the way into Luton town centre.
“I would like to hear from anyone who may have been in the area at the time who may have witnessed the attack, or seen a group of four men dressed in dark clothing acting suspiciously.”
Anyone with information is asked to contact DC Harris via 101. Alternatively you can contact Crimestoppers anonymously on 0800 555 111.