Fake ambulances were used to smuggle £1.6 billion (NZ$3.68 billion) of drugs across the Channel to Britain, a court heard.
Three Dutchmen were involved in the "lucrative conspiracy" to import cocaine, heroin and ecstasy, concealed from border officials with the aid of bogus paramedic uniforms and even fake patients on crutches.
Leonardus Bijlsma, 55, now faces a lengthy jail term after being convicted of drug smuggling following a two-week trial at Birmingham Crown Court.
Olof Schoon, 38, said to be the "central player" in the operation, admitted a charge of conspiring to smuggle drugs.
A second man, Richard Engelsbel, 51, admitted the same charge. Another man, 28-year-old Dennis Vogelaar, was acquitted by the jury of smuggling.