Just after 4:20pm yesterday, the officer was called to the event gate to report that the man had been assaulted.
West Yorkshire police said the man was taken to hospital, but he “rejected treatment.”
The police were in place while the police were making inquiries.
A West Yorkshire police spokesman told Telegraph & Argus this morning:
“The officers were called at 4:21pm and reported that the man had been assaulted.
“He was taken to the hospital where he refused treatment.
“The scene was introduced while Bradford CID was inquiring.
“Anyone who witnessed the assault is asked to contact the police via 101 or use the live chat facility at www.westyorkshire.police.uk/livechat.