The organisers of London's Bloc festival have issued a statement to apologise for the cancellation of the event.
The Met Police blamed poor weather conditions for the decision to close the venue, which was taken in the early hours of Saturday morning.
The event took place at The London Pleasure Gardens, a temporary event space in the East End. Fans paid up to £125 a ticket to see stars like Snoop Dogg and Orbital.
Many complained of overcrowding from the start, with long queues to get into the festival, compounded by equally long waits trying to get into individual tents on site.
Organisers have issued a statement on their website which reads: "We are so sorry what we couldn't deliver the experience we had planned."
They also say they are working to ensure that everyone will be refunded for their tickets.
More top news
The Met Police has thanked residents in Northolt for their patience but has warned the armed stand-off could take time to resolve.
A man said to be armed with dangerous articles remains inside an address in west London.
British Bankers' Association head Anthony Browne warned that some banks could be moving abroad within weeks due to Brexit uncertainty.