Achilles Macris, who is appealing, ran the London division of JPMorgan's Chief Investment Office, where Bruno Iksil, nicknamed "the London Whale" for the size of the his derivatives trades, stacked up huge losses, more than $6.2 billion (3.8 billion pounds) at last count.

JPMorgan agreed to pay $920 million in penalties last month to the U.S. Federal Reserve, the U.S. Securities and Exchange Commission, the U.S. Comptroller of the Currency and the UK's Financial Conduct Authority (FCA) over the trading scandal.

The FCA notice of its fine, totalling 137.6 million pounds, did not mention Macris by name but said that "by virtue of the conduct of the CIO London management" JPMorgan had deliberately misled the regulator.

A spokesman for Macris said he had not been given a proper opportunity by the FCA to respond to the criticisms before they were published.

"Mr. Macris strenuously denies the assertions made by the authority in the final notice as being factually wrong. Those assertions fail to take proper account of the actions he took and mischaracterise his dealings with the authority at the relevant time," said the spokesman in an e-mailed statement.

FCA spokeswoman Lara Joseph was not immediately available to comment, nor was a JPMorgan spokesman.

Jamie Dimon, chief executive of the New York-based bank, characterized the $6.2 billion loss last year as "the stupidest and most embarrassing situation I have ever been a part of."

Iksil's former boss, Javier Martin-Artajo, and junior trader Julien Grout were indicted in the United States in September on five charges each, including securities fraud and conspiracy, for seeking to hide losses as they began to mount. Iksil has not been criminally charged and has been cooperating with U.S. authorities.

Martin-Artajo and Grout are not in the United States and haven't returned to face the charges. Macris was Martin-Artajo's supervisor.

(Reporting by Kirstin Ridley; Writing by Carmel Crimmins; Editing by Steve Orlofsky)