Toy guns given away as funfair prizes presented a headache for police, who kept receiving reports of people carrying firearms at the Under One Sky event on Sunday.
But Inspector Andy Jackson, from Wealdstone police station, who oversaw policing for the event, said besides this inconvenience, there were only three arrests all day,all for public order offences.
He said: "There were no arrests for weapons and nobody turned away."
He pointed to the effectiveness of a new tactic to place metal detectors at the entrance to the event.
In all, 80 officers, including 15 police cadets and 16 special constables, monitored the event and traffic on roads surrounding Kodak Sports Ground.
Insp Jackson said: "There was a funfair and some of the prizes being supplied were plastic toy guns so it would be correct to say there were lots of 'guns' in the crowd.
"We had no reason to doubt they were toys and it was dealt with each time with the appropriate level of response.
"With a large group of people, you're going to get an element that could be disruptive, so when we come away from the event, we want to come away with public safety intact and that's exactly what's occured here, so that's a success."
