London Whale boss's prestigious pad appears empty

JPMorgan Chase
Adam Jeffery | CNBC

Javier Martin-Artajo, the former JPMorgan executive reported to be under threat of arrest over the "London Whale" trading losses, escaped the City to a prestigious country address — which appeared empty on Monday.

Media reports on Friday suggested Martin-Artajo and former colleague Julien Grout could be arrested within days, on charges of masking a multi-billion dollar trading loss, which has cost the bank more than $6 billion. However, Martin-Artajo's house was unoccupied on Monday, and neighbors told CNBC he might have left the country.

(Read more: Authorities plan to arrest 2 former JPMorgan employees in 'London Whale' case)

The banker lives in Chipping Norton in the Cotswolds, a short drive from the homes of Prime Minister David Cameron and former News Corp executive Rebekah Brooks, who will contest charges related to phone hacking at London's highest criminal court in September. The area and its inhabitants, known as the 'Chipping Norton set', came under the spotlight last year when it emerged that Cameron had ridden a horse Brooks had been given by the Metropolitan Police, in a story seen by some as highlighting the close links between News Corp, the government and the police.

Martin-Artajo and his wife Sarah were at their sprawling property in the area with their children until Saturday morning, when they left, two neighbors told CNBC. This followed reports in the U.S. on Friday night that he was likely to be arrested imminently, although one neighbor said that the family was often away during the summer months.

On Monday, there were only cleaners in the house, a classic Cotswolds stone home in a small country village. Neighbors did not know when the family were planning to return, or where they had gone.

Martin-Artajo did not respond to requests for comment. He has previously denied wrong-doing through his lawyer, and JPMorgan dropped a lawsuit against him over the losses. He managed Bruno Iksil, the trader who was labeled the 'London whale' because of the size of his trades, which were big enough to affect global credit markets. Iksil claimed to have told Martin-Artajo the size of his positions were "scary" early in 2012.

(Read more: Jamie Dimon defends actions in Whale case)

If Martin-Artajo is to be prosecuted, it will be in the U.S., where a Senate report criticized JPMorgan's management of the trades earlier this year. Martin-Artajo is a native of Spain, which has an extradition treaty with the U.S.

Follow Catherine on Twitter: @cboylecnbc