Images show what has been described as a "heartbreaking" amount of litter piled up on a beach in one evening.
Empty bottles and paper plates were among the items strewn across Margate beach, in Kent, on Saturday.
Thanet District Council cleaned up the litter and is working to identify those responsible.
Bob Bayford, the council leader, said the local authority is liaising with the organiser of an event which attracted 500 people.
Photographs emerged over the weekend of the waste left at the seaside spot at a time when the council is campaigning for cleaner beaches.
Mr Bayford said: "We love to see people enjoying our beautiful sandy beaches but the mess that was left on Saturday was shocking and heartbreaking to see.
"There were a number of groups on the beach on Saturday and permission had been granted for a 500-person event, at the Nayland Rock end."
Mr Bayford added: "Despite the provision of commercial bins and bags by the council as well as empty bins on the promenade, there was still a huge volume of litter left on the beach.
"We are reviewing CCTV footage and liaising with the event organiser in regards to their deposit and potential enforcement action."
He did not provide details of the event.