Police officers were stunned to find they had been called to a sci-fi convention to break up a scrap between Doctor Who and Judge Dredd.
The spat was between a fans dressed as Star Wars characters including a Sith Lord and two Whovians dressed as different regenerations of the Time Lord.
The treasurer of the Norwich Star Wars Club UK convention Jim Poole, 44, started the trouble by asking for an autograph from The Bill actor Graham Cole, who has also played a Cyberman in Doctor Who.
The signatures were being collected for a Doctor Who diary which was to be auctioned off for charity.
Norfolk Police attended the incident where one fan had allegedly told the other he would “knock his f****** head off.”
The sci-fi and film convention was the fourth arranged by the Star Wars fans at The University of East Anglia.
Event organiser Richard Walker said the scuffle was the result of a build up of tension between the two camps in fancy dress.
The 63-year-old said: “I asked him what he was doing there. I told him I wanted him I wanted him to go because he’d caused trouble in the past. But he refused to leave. There has been a long running saga.”
Richard then proceeded to guide him out of the convention, after which Jim rang Police believing he had been the victim of a common law assault.
Jedi Jim, of Lowestoft, said: “Mr Walker was abusive and threatening, saying he’d ‘knock my f****** head off’.
“I was put in a Police car. We were both interviewed by the Police and told to stay away from each other.”
After viewing CCTV footage of the incident, Police concluded that Jim had not been assaulted.
The two clubs are in discussions to plan a meeting to resolve their differences.