Staff on the Tyne and Wear Metro were incredulous when the smartly-dressed, well-spoken, young man they stopped on a routine ticket check gave his address as Floors Castle in Kelso, Scotland.

It was only when he showed them his driving licence that they believed he really was Charles Robert Innes-Ker, the Marquess of Bowmont and the future Duke of Roxburghe.

Lord Charles, 21, who is the nephew of Britain's richest man, the Duke of Westminster, was caught at Haymarket station in Newcastle city centre after travelling in from the Jesmond area.

He's got 21 days to pay his fine and if he doesn't his name will be on the losers' posters Nexus spokesman

He opted not to pay a �10 on-the-spot fine but must send the cash to operators Nexus within 21 days or be taken to court.

Lord Charles could then face a stiffer fine and have his name placed on a published "Losers' List" of fare dodgers.

A spokeswoman at Floors Castle said the family did not want to comment about the incident.

A Nexus spokesman said the Marquess was picked up without a ticket on 3 February at 1500 GMT at Haymarket in a monthly operation to catch fare evaders, called Operation Nemesis.

He added: "We thought he was a student as he gave us his parents' address but the customer service assistant thought he was having her on when he said it was Floors Castle in Kelso.

"But then he showed us his driving licence which said he was the Marquess of Bowmont.

'Fare dodgers'

"We were certainly amused by it what with his title and his position.

"But there is a serious side to it in the sense that we lose �1m a year due to fare evaders.

"He's got 21 days to pay his fine and if he doesn't his name will be on the losers' posters."

The ancestral home of Lord Charles, Floors Castle, is set in 60,000 acre grounds and boasts its own �1.5m championship golf course.

It was also used as a setting for the film Greystoke: The Legend Of Tarzan, Lord Of the Apes.