Five people have been arrested and fined in connection with a forest rave attended by more than 500 people.
More than 100 officers were deployed to break up the unlicensed music event in Thetford Forest, Norfolk, on Saturday at 23:20 BST.
Officers shut down the rave by 18:30 on Sunday.
Since Friday police in England have been able to fine organisers of illegal gatherings of more than 30 people – such as raves – up to £10,000.
Officers seized audio equipment, generators, a rig and a large flatbed lorry which was used to transport the equipment to the forest.
Police said five people were arrested – three were issued with £100 fines at the scene while two were taken in custody and later fined £100.
Assistant Chief Constable Nick Davison said: “We understand the disruption such events cause to local communities and the concern people will have, particularly as coronavirus continues to be a real threat.
“This was a well-established and planned event and we needed additional specialist resources to shut it down safely.”
Elsewhere, police attended events in Leeds, Essex and the West Midlands, while Piers Corbyn, the brother of former Labour Party leader Jeremy Corbyn, was fined for holding an anti-lockdown protest in Trafalgar Square on Saturday.
In London, the Metropolitan Police said it had shut down 21 unlicensed music events, with 58 reported to them on Saturday.
West Yorkshire Police said eight people were fined £10,000 after several parties across Headingley and Burley on Saturday and into the early hours of Sunday.
Police in Harlow, Essex, seized thousands of pounds worth of equipment ahead of an unlicensed music event on Saturday afternoon.
Ch Insp Lewis Basford said the force would be “looking to identify the organiser and take them to court”.
West Midlands Police said it had dealt with about 90 reports of possible breaches of restrictions, but had not had to use its enforcement powers.
Home Secretary Priti Patel has said the new legislation represents a crackdown on “the most serious breaches of social distancing restrictions”.