Brentford County Court in west London has given permission for Carlos Corredor-Gonzalez to bring a civil action against the department for the return of the stone or appropriate compensation.
Corredor-Gonzalez is at present serving an 11-year prison sentence for importing two kilograms of cocaine into Britain in 1994.
He alleges that the valuable gem has gone missing from his personal possessions, which were seized by Customs officers when he was first arrested. According to lawyers for Corredor-Gonzalez, Customs has admitted taking possession of a "green stone" but does not accept it was a gemstone worth pounds 10,000.
Corredor-Gonzalez is due to be released on parole from Maidstone prison, Kent, in October in time to appear in his civil case at the Brentford court, after which he is expected to be deported to Colombia. His lawyers will claim that he handed over the emerald, which was logged by Customs as "an envelope containing a small green coloured stone".
The stone disappeared when Corredor-Gonzalez's belongings were transferred to Wandsworth prison in south London. The Prison Service said that it did not take possession of the stone when his other personal belongings were handed over.
Corredor-Gonzalez claims that the emerald was handed down to him by his grandmother in 1992. He says the stone was extracted from the famous Muzo mine, a site once known for its highly prized gems.
Harry Levy, a Hatton Garden gemstone dealer, confirmed the existence of the mine and its reputation for producing high-quality emeralds.
"In the past if you said you had a Muzo emerald people would have gasped, like they would with a vintage wine. Muzo used to be very productive but has dried up over the last 100 years."
The emerald is one item on a list of 10 possessions that Corredor-Gonzalez claims were never returned.
These included his identity cards, without which he risks arrest upon his return to Colombia and which he needs to obtain legal work. Corredor- Gonzalez is making a further claim of pounds 5,000 for the loss of these items and the resulting inconvenience.
His lawyers said that if Customs does not offer compensation then the drug runner will make a further claim for negligence in losing the stone.Reuse content