Police revealed they arrested a 14-year-old Northampton boy following a 4am street fight in the town centre.
A 21-year-old Londoner and an 18-year-old from Northampton were also detained after two gangs clashed in the middle of Drapery, near the corner of Gold Street, during the early hours of Sunday morning (July 25).
One of the groups produced bottles containing an unknown substance which they attempted to squirt over the others involved.
Officers say the town was packed with revellers at the time and believe some onlookers filmed the fight on mobile phones and are keen for anyone who has footage to get in touch urgently.
A Northamptonshire Police spokesman said: "The incident took place at about 3.50am on Sunday in the middle of the road. A scuffle between two groups soon escalated into a fight.
"One group attempted to squirt the other with bottles containing an unknown substance but fortunately, no one was hurt as a result of the incident.
"We would urge any witnesses or anyone with information which could help our investigation — particularly mobile phone footage — to call 101 or contact Crimestoppers anonymously on 0800 555 111 using our incident number 21000415862."
All three people arrested in connection with the incident have been released on police bail pending further enquiries.
One inspector confessed via Twitter: "Custody was busier than I have ever known" as nightclubs reopened and pubs were able to ditch table service only rules on the first weekend since Freedom Day.
Three assaults on police were reported among a number of incidents on Friday and Saturday night — although senior officers insisted that the vast majority of people had been well behaved.