Police in Cornwall have confirmed they filmed an event in which locals black up their faces and dance through the streets of a Cornish town.
The event is thought to date back more than 100 years
Police shot video of the most recent "Darkie Days" in Padstow and have submitted a file to the CPS.
Police said their action was connected to "allegations of disorder".
But officers would not confirm reports that they had received complaints that the events amounted to incitement to racial hatred.
The festivities in the pretty fishing town are thought to have gone on for more than a century but have caused controversy in recent years.
In 1998 the late Bernie Grant, who was Labour MP for Tottenham, condemned the tradition as "offensive to black people all over the place".
Devon and Cornwall Police confirmed they had footage of the event on Boxing Day last year and New Year's Day.
A force spokesman said: "The footage has been sent to the Crown Prosecution Service for them to consider what, if any, offences have been committed.
"As they still have this matter under consideration, it would be inappropriate for the police to comment further at this stage."
During the festivities, revellers raise money for charity by dancing around the town and singing songs traditionally associated with the plantations.
Its origins are unknown but one theory, now widely discounted, is that it dates from an occasion when local people saw black people dancing and singing aboard a slave ship which had been forced to seek shelter in the harbour.
Local district councillor Sarah Townrow said on Thursday Padstow residents were "fed up with being pushed around".
She warned Britain was becoming a "nanny state", adding: "Nobody has got any malice in them.
"I am sure there is no more trouble goes on at Darkie Day than at any other celebration in any town in the country.
"We just want to be left alone to enjoy it."