HE is a scion of one of Scotland’s most noble families, whose seat of Cawdor Castle was immortalised in literary history as the home of Lord Macbeth.

But now the hitherto gilded life of Jack Marrian appears to have been infected by the so-called Curse of Cawdor after he was arrested in connection with the smuggling of cocaine worth £4.5 million into Kenya.

Mr Marrian, heir to the 14th century Cawdor Castle near Nairn, is being held in Kileleshwa police station, Nairobi, after police found the drugs in a shipment labelled as sugar imported by his company.

The 31-year-old, who attended Marlborough College, where the Duchess of Cambridge studied, is managing director of Mshale Commodities, the Kenyan importer who received the drugs.

His family have insisted he is innocent and have vowed to clear his name, but prosecutors say he would have known about the shipment.

Mr Marrian’s father David, an artist who lives in Kenya, said: “I know, and I’m pretty certain police know, he is innocent but this is Kenya and we are terrified of the repercussions.

“But we have good lawyers and we know he is innocent and the Kenyan judiciary has changed. We know the truth will come out.

“But it’s properly frightening.”

David Marrian said his son was being looked after while in custody but was “incredibly distressed”.

He added: “The sugar in the containers was being sent to Jack’s company but he has no involvement in either the packing of the ships or the unloading. The containers are not his. The ship is not his.

“The fact it is contaminated with cocaine has nothing to do with him. The containers are packed in the port and checked by an independent company approved by Kenyan customs. There is a seal put on the container but it is not a foolproof system.”

Mr Marrian is the son of Lady Campbell of Cawdor, daughter of the late Hugh Campbell, the sixth Earl Cawdor.

His grandfather was the artist Hugh John Vaughan Campbell, the sixth Earl and custodian of the castle in Nairn. The family seat has been the subject of a bitter dispute after Mr Campbell left it to his second wife, Czech-born Angelika Cawdor, instead of to his son Colin.

The feud became known as the Curse of Cawdor after it split the family. The Earl’s daughter Liza Campbell, Jack Marrian’s aunt, later wrote an autobiography, Title Deeds, in which she claimed her father was a violent drunk, and likened her stepmother to Lady Macbeth.

The memoir detailed how her father’s behaviour tore the family apart, and recounted his womanising and drug-taking.

Ms Campbell, who married a big game fisherman and lived on a desert island for a spell, also alleged that her father tried to get her into his bed when she was 16.

Liza Campbell, meanwhile, insisted her nephew had nothing to do with the drugs. She said: “Jack is a hard-working, loyal employee of a large, respectable sugar company.

“He has been thrown into a nightmarish situation by a perfectly normal consignment getting contaminated by smugglers during international transit.

“He is completely innocent and we are confident that the Kenyan police will exonerate him soon.”

A spokeswoman for Mshale Commodities said: “Mshale is aware of speculation regarding an allegedly compromised shipment consigned to Mshale Commodities. We can confirm that Mshale’s managing director, Jack Marrian, is assisting the Kenyan authorities to provide them with whatever information they require.

“Mshale operates stringent procedures to protect the integrity of its supply chain. Until these investigations are concluded, we are unable to comment further.”

A National Crime Agency spokesman said: “We are aware of the seizure and the subsequent arrest of a UK national, and have assisted our Kenyan and US law enforcement partners. This is now a matter for the Kenyan authorities so it would not be appropriate to comment further at this time.”