South Yorkshire Police provoked fury on Saturday by deploying a helicopter to hover menacingly over a festival marking the 30th anniversary of the Battle of Orgreave.

The family festival and picnic took place near the site where thousands of police savagely attacked striking miners during the 1984-5 strike against pit closures.

Many of the 1,500 people present had already left the peaceful day-long festival but after 6pm a police helicopter began circling the site, eliciting shouts of protest and angry gestures from the few hundred remaining.

Granville Williams, who ran a stall for the Campaign for Press and Broadcasting Freedom, said: “I turned and saw it hovering.

“People said it was intimidating, frightening. It came quite low down and hovered.

“People were giving it V-signs, showing their contempt.

“But why was it there? Police don’t seem to have learnt anything from the anger they caused 30 years ago.”

Police were unable to explain yesterday why the helicopter was deployed.

A spokeswoman said: “I haven’t been made aware of anything regarding the event, so I don’t believe it will have been for a critical incident. The only thing I can assume is that it has looked there to see everything was OK.”

South Yorkshire Police co-ordinated the Orgreave attack on the miners and its role has been referred to the Independent Police Complaints Commission, which has spent 18 months deliberating over whether or not to investigate.