A rugby match between two rival Cambridgeshire private schools erupted in violence after an 18-year-old man was allegedly assaulted during the game.
Spectators at the game between two of Cambridge's most expensive independent schools claim that one player was 'almost knocked out' in an 'unprovoked' attack.
Police were called to the match between £33,000-a-year The Leys School and £18,000-a-year The Purse School shortly after 3pm on Saturday.
One person who claims to have watched the game said on a local new site: "I Would like to mention, that as a spectator there on Saturday, it was a Leys player who was attacked totally unprovoked by a Perse student.
"Not at all in line with how rugby should be played or indeed how any sport should be played. Poor Leys player was almost knocked out cold."
"It wasn’t a player on the pitch, a Perse substitute walked on from sideline and attacked a Leys player. Hence why the referee couldn’t just deal with it alone."
The Perse School's head of Sixth Form Richard Morgan email pupils urging them to "avoid telling people on social media".
He wrote: "Many of you will be aware of an incident that occurred during the Perse v Leys 1st XV fixture today.
"Naturally there will be many people linked to both schools who have seen or heard about this and they may want to express their views.
"Please can I urge you not to put any comments on social media – this will not be helpful and it is important to avoid posting anything that might later be a cause for regret.
"I also advise you not to get involved in any conversations about it, particularly at any social gatherings you may be at this weekend.
"If you are approached about this incident by anyone and feel uncomfortable with something that is said or you become aware of anything being said on social media about it, I strongly urge you to let me know."
The Leys headmaster Martin Priestley later tweeted to congratulate his school's first team for the 11-10 win on Saturday,
Police confirmed an investigation has been launched but that it is still determining the facts of the event.
He said: "We were called at around 3pm on Saturday (December 1) after reports of an assault on an 18-year-old man during a rugby match at the Perse School in Hills Road.
"We have no further information at this time and will be carrying out an investigation."
A further police statement read: “Officers spoke to the alleged victim, who was safe, and an appointment has been made for him attend a police station.”
The Leys and The Perse School have been approached for comment.