image copyrightJohn O'Sullivanimage captionA line of police vans was pictured on the approach to the illegal party in the national park
More than 50 people have been arrested after an illegal rave attended by up to 2,000 people at a national park.
Sussex Police said it was met with "significant hostility" as it shut down the event in Steyning, on the South Downs in West Sussex, on Sunday.
One officer was assaulted and another was treated for a suspected broken arm after a crash at the scene.
The force described it as "one of the largest unplanned operations we have experienced in recent years".
Those arrested were taken into custody on suspicion of offences including drink and drug-driving, possession of drugs and theft.
'Damage and distress'
Under current coronavirus rules, gatherings must not exceed 30 people unless covered by a legal exemption.
Videos on social media showed large crowds which had gathered on Saturday night, partying into the morning with professional sound and lighting systems.
Local farmer James Wright tweeted that the unlicensed rave had led to "terrified cattle" and "a lot of mess".
In a subsequent tweet Mr Wright, who is also a Horsham District councillor, said: "Those who attended might think they've had the best of times but genuine damage and distress has been caused to those that live and farm here."
image copyrightJohn O'Sullivanimage captionPolice seized a large amount of musical equipment
Dozens of cars lined the country roads, with some abandoned on verges, on Sunday morning.
Sussex Police said a directive to leave the area was issued at 17:45 BST and the event was finally brought to a close at 19:15 BST on Sunday.
Musical equipment was seized by officers and eight people were identified as suspected organisers and arrested.
There were two crashes involving police cars.
In the first, an officer was injured in a collision with a vehicle leaving the event.
The driver and passengers were taken to hospital "as a precaution" and a 20-year-old Redditch man was arrested on suspicion of drink and drug-driving.
image copyrightRichard Williamsimage captionThere was a significant police presence in Steyning on Sunday
In a second crash, a driver was arrested on suspicion of failing to stop, dangerous driving and failing to provide a breath test.
Det Supt Juliet Parker added: "Due to the mindless actions of a large number of people, the majority of whom have travelled from out of county, the community of Steyning has experienced significant disruption.
"These individuals have demonstrated a complete disregard for the local community, the heritage of the area and the existing Covid-19 regulations."
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