More than 40 people are facing fines of £800 after they were caught at an illegal rave in the vault of a disused bank.
Officers were on patrol when they heard loud music on Hortus Road, Southall, at around 08:51hrs on Sunday, 7 March.
On closer inspection, they identified the source of the noise as coming from a derelict building.
They discovered that 44 people had made their way in through a gap in a fence and inside the building to set up a DJ equipment with speakers.
After additional officers were requested, police entered the venue and reported all in attendance for consideration of a fixed penalty notice for £800 before removing them from the premises.
Enquiries continue as officers work to track down the organiser of the event.
Detective Chief Inspector Thomas Bowen from the West Area Command Unit, which covers Ealing, said:
“It is disappointing some selfish people still insist on breaking Covid regulations. We are all excited about the prospect of returning to normal in June - and some changes to restrictions are imminent – but behaviour like this risks undermining the roadmap out of lockdown and could potentially cause further delays by creating a breeding ground for the virus.
“We will continue to do our part in shutting illegal events like this down and taking action where necessary.”