A martial arts expert is in a serious but stable condition in hospital after he was struck on the head with a sword during a medieval battle re-enactment.
The martial arts expert was hurt during the re-enactment
The 30-year-old Kieron Robb, from Scotland, was among 150 people taking part in the mock fight in Clapham, Beds, when the accident happened.
Hundreds of spectators saw the man injured on Saturday afternoon.
Officers appealed for anyone filming the event who has footage of the accident to contact them.
Det Sgt John Walters said: "Although the incident is not being treated as malicious, it is important police have as complete a record as possible.
"The other man involved has co-operated fully with the police but is obviously very distressed and shocked."
Mr Robb, a renowned swordsman with years of fighting experience, was struck close to his eye.
He was taken to Bedford Hospital, but later transferred to Addenbrooke's Hospital in Cambridge for treatment.
Event organiser Dave Smith said: "What I have been told by people who were on the field is that this was a freak accident caused by a deflected sword strike."
He said that such events had an excellent safety record.
"This is really quite a shock to everybody involved," he added.
"It is probably the most serious incident in medieval re-enacting that anyone can remember."