A man was chased into a betting shop and then set upon by a gang carrying metal poles, golf clubs and spanners.
The victim was subjected to an attack lasting up to 90 seconds by three masked men in Corals betting shop in Crawley High Street at 4.30pm on Sunday.
A man was chased into and then around the shop before taking blows to his body and face from a series of weapons and from shop furniture being thrown at him.
The victim left moments after his attackers with a bloodied face but appeared to staff to be reluctant to engage with staff or to phone the police.
PC Ben Easton said: "At this stage we do not know the motive for this vicious attack, or who the attackers or the victim are.”
Anyone with information should contact Susses Police via 101 quoting serial 0985 of December 2.