British police said on Saturday they had found no evidence to charge anyone with a terrorism offence linked to a suspected threat against an Islamic event in eastern England last weekend.
Thirteen people had been arrested between Sunday and Thursday after police became aware of a "potential serious threat" towards the religious event, attended by about 15,000 people at a country house in Suffolk.
Of those, eight men had been detained under the Terrorism Act but seven of them were released without charge on Saturday, the police said.
The remaining man, 42, was charged with possession of offensive weapons — extendable batons — and the possession of a stun gun, after items were recovered during searches.
Police said those offences were not believed to be connected to the alleged threat.
"We have found no evidence to support anyone being charged with any offences linked to the alleged threat," Commander Helen Flanagan, head of Counter Terrorism Policing London, said in a statement.
She said enquiries were ongoing and that police would not hesitate to take further action if threats to the public were identified.
Officers seized more than 35 digital devices during the investigation, which included searches of homes and vehicles.
Britain raised its national terrorism threat level to "severe" in April, signalling that an attack was considered highly likely.
Interior minister Shabana Mahmood said last week that she knew the arrests would be concerning for British Muslims.
Flanagan said she wanted to reassure the Muslim community that enquiries were continuing.
