Tests showed a white powder found within the walls of the horsebox was cocaine
Cocaine with an estimated street value of £3m has been found hidden in a horsebox.
The drug was discovered in an internal wall of the animal carrier at Harwich International Port last week, the Border Force said.
A 32-year-old Hungarian man and two women from Germany, aged 42 and 50, have been arrested and bailed pending further inquiries.
The Border Force said two horses were being cared for by a local charity.
The horse carrier had travelled from the Hook of Holland and was stopped on 26 March
The drugs were discovered after a scan revealed an "anomaly" in one of the walls in the horsebox.
Phillip Holliday, Border Force regional director, said: "Although this was an unusual and well-hidden concealment, the vigilance and expertise of Border Force officers has foiled an attempt to smuggle a large amount of class A drugs, with an estimated street value in excess of £3m, into the country."
