POlICE were told there would be a rave at the Royal Mail depot in East Croydon more than a week before it happened.
The Met received intelligence on June 5 that there would be an event at the former delivery office, in Cherry Orchard Road, on Saturday (June 14).
An internal investigation is underway after the information was reviewed by an intelligence officer but no further action was taken.
A 15-year-old boy who attended the rave died in hospital today (Monday). Police believe he drank from a bottle of beer which contained ketamine, the Advertiser understands.
Thousands of people attended the rave after receiving an email on the day containing mobile phone numbers to call in order to find out the location.
Publicly, police have said they first became aware of the rave at 9.40pm, when officers on a routine patrol noticed people in the building and crowds outside.
Riot police were called but instead of stopping the event a cordon was put up and it was allowed to continue.
The extent to which police were pre-warned of what was going to happen was discussed at an emergency meeting with the council and other agencies this afternoon.
That 'gold group' meeting heard that police had information which said a rave was going to take place at the delivery office, which closed earlier this year.
Royal Mail had also informed police the building had occupied by squatters in the week leading to the event.
A Met spokesman told the Advertiser: "We received a single piece of intelligence that an event may take at the location.
"The information was reviewed by a local intelligence officer, but not further action was taken.
"We are now conducting an internal review into how this intelligence was handled."
Croydon Central MP Gavin Barwell said today: "If it is true that the police knew about it and didn't make sure they had sufficient resources in place to put a stop to it then it's a very serious matter."
As huge numbers of revellers arrived via East Croydon station, riot officers were called in after police trying to shut the party down had objects thrown at them, including fire extinguishers.Video showing crowds throwing objects at police
Officers then stepped back and allowed the rave to continue amid concern the disorder could spread.
They remained at the scene, along with ambulance crews, and then moved in at around 8.30am to clear and secure the building, which suffered extensive damage, including dozens of broken windows.
In January, Croydon student Daniel Spargo-Mabbs, 16, died after taking ecstasy during an illegal rave in west London.
In April, a rave in a warehouse in Bath House Road, just across the border in Sutton, attracted a crowd of more than 3,000 people. So far 14 people have been arrested for various offences as part of a major investigation into the disorder on Saturday, five of whom were arrested today and remain in police custody.
Two people were charged an appeared at Camberwell Green Magistrates' Court via video link today.
