Police were called to a science fiction convention after an argument between two rival groups of fans.
Trouble flared at the fourth Norwich Sci-Fi and Film Convention at the University of East Anglia, organised by Norwich Star Wars Club.
Police were called after members of the rival Norwich Sci-Fi club arrived to get autographs from two Doctor Who actors at the event on Sunday.
Norfolk Police confirmed officers attended and spoke to both parties.
A spokesman said they had been called to reports of a man being assaulted at the convention.
It kicked off when angry organiser Richard Walker, of the Norwich Star Wars club, saw Jim Poole, 44, of rival Norwich Sci Fi Club filming the family event with two fellow Time Lord fans, one dressed as David Tennant.
Mr Walker, 63, said: “The person on the door had not not recognised them. I put my hand on Mr Poole’s arm to escort him off the premises and he said I had assaulted him.”
More than a dozen people then became involved in a bitter row at the University of East Anglia, where 1,000 sci-fi fans had gathered, many dressed as Stormtroopers.
Police arrived and put one Who fan in a car before calming things down. They decided there was no assault.
Mr Walker said the visiting club had been trying to undermine and embarrass the convention by posting comments on social media sites such as Facebook.
But Mr Poole said he had attended “in good faith” to collect autographs from two actors for a Doctor Who signature diary to be auctioned for charity.
Both sides said there had been a long-running rivalry between the two groups and the events they organise.