RAVERS breaking into a Grade II-listed building to hold illegal parties will face stiffer security in future, a council has promised.

Partygoers have been using the pedestrian subway under Crystal Palace Parade in Crystal Palace Park as a venue over the summer.

Bromley Council is aware of two illegal parties at the subway arches - the most recent being held overnight between August 4 and August 5.

The raves are believed to be held on a six-week cycle but the park's staff did not discover the first one, on June 23, until after the event.

The problem of illegal parties at the 19th-century pedestrian subway was raised by Councillor Michael Tickner at a council meeting on Monday.

Cllr Tickner asked portfolio holder for environment and leisure Councillor Colin Smith what action he has taken to increase security at night and if he would be prepared to set up an action group to tackle the problem.

Cllr Smith confirmed park staff had found about 100 revellers in the subway area on the morning of August 5, hours after police had closed down the party.

He said: "The park's staff contacted the police again and a request was made by our staff to arrest the organiser and impound the equipment. The police were unwilling to do either.

"The police requested we open a nearby park gate to allow the organisers to bring their vans into the park to allow them to move the sound equipment."

He added: "It was clear an angle grinder had been used to gain access to the subway.

"Additional heavy duty locks have now been fitted to the site and additional physical measures are being taken to make access to the subway more difficult.

"Park staff will be covering the subway area after normal park closing times at weekends until the end of September, when the situation will be reviewed again."

London Assembly member for Lambeth and Southwark Valerie Shawcross received complaints about the rave on August 5 from residents in Burnt Wood Road, close to the subway on the north-west side of the park.

Ms Shawcross said: "The premises may be damaged.

"The people organising these events aren't just trespassing, they are breaching health and safety.

"Bits of the balustrade have broken off and had to be fenced off.

"People are putting themselves at risk by going to these parties."

The council said the building had not been damaged during the raves but it was said to be at risk of slow decay in a survey of historical buildings at risk published by English Heritage in August.

Crystal Palace Park Working Group is a voluntary group consultated over the park.

One of its members, Karen Moran, said: "The subway was part of the Crystal Palace walkabout tour for tourists until we had to stop going there because it was getting dangerous.

"At the top of the subway the brickwork is falling down, but the problem is money.

"It is starting to look a bit derelict, which is why people are using it for parties."

Police confirmed a gathering of people had been dispersed from the subway site on August 5 but a spokesman was unavailable for further comment on the incident.