More than 400 people were still at the Litlingham barn on Sunday

Thousands are thought to have attended the illegal parties at the weekend.

An unlicensed rave near Santon Downham, on the Norfolk/Suffolk border in Thetford Forest began on Saturday and continued on Sunday.

Alexandra Jarvis, of Litlington, Cambs, said a nearby rave was "noisy, disturbing, and frustrating", especially when police would not act.

She told BBC Look East she called police at 0230 BST on Sunday and was told there was nothing they could do.

I never want to be seen as a party pooper, but it is very disturbing at night to hear a noise going on and on and on Alexandra Jarvis

She was advised to call the local Environmental Health department on Monday morning.

"But the ravers would be gone by then, so the noise levels could not be measured," she said.

More than 400 people were still inside the barn at Litlington, near Royston, on Sunday morning.

Summer is the season for raves and with its proximity to London, the region is a popular venue.

'Good-natured' ravers

There was another rave at Wolverton Woods at Dersingham, Norfolk, which is part of the Crown Estate and a smaller gathering in Northamptonshire.

In Bedfordshire officers stopped illegal raves at Toddington and Clopton over the weekend after calls from the public.

Police said they try to disperse revellers before a party starts, but admit that once it is under way the numbers involved and the lack of any criminal offences being committed make it hard for them to act.

Police described the rave in Thetford Forest, with more than 1,000 revellers, as "good-natured and friendly."