* Original fine on Hannam confirmed after court battle
* Hannam has until August 7 to pay
* Regulator urges financial professionals to heed judgment (Adds Hannam and lawyer comment, details, background)
LONDON, July 22 (Reuters) - Britain's financial watchdog has upheld a 450,000 pound ($768,000) fine on former JPMorgan banker Ian Hannam - a prominent dealmaker once dubbed the "king of mining" - for market abuse after a protracted court battle.
In an effort to clear his name, Hannam had fought to overturn the Financial Conduct Authority's (FCA) initial findings and fine of 2012. But in May, he lost his appeal in a landmark case that fuelled a high-level debate about how confidential information should be treated during deals.
The former soldier, who became one of London's most prominent investment bankers renowned for his bulging contacts book and knack for a new idea, was awaiting news about whether the original FCA fine would be upheld - one of the largest levied against an individual in Britain.
Imposing the penalty, the head of the FCA's enforcement and financial crime division Tracey McDermott urged all financial professionals to pay close attention to a judgment that did not question Hannam's integrity, but sought to bring clarity to the grey area of what constitutes acceptable business conduct.
"It (the Tribunal judgment) should leave market participants in no doubt that casual and uncontrolled distribution of inside information is not acceptable in today's markets," she said on Tuesday.
Hannam, dubbed "king of mining" because of his weight in the resources sector, said he had decided against appealing the Tribunal decision and said he hoped his decision to challenge the FCA findings would ensure others were now better able to understand the scope and effect of inside information rules.
"I now wish to put this difficult period behind me and get on with my business career," he said in a statement published on his website, thanking JP Morgan, friends and family who stood by him during "these difficult five years".
The case hinged on two emails Hannam sent in 2008 to Iraqi Kurdistan's oil minister Ashti Hawrami on behalf Heritage Oil , a client, which the regulator alleged included potential inside information about a potential takeover and a potential oil discovery.
No-one traded on the information in Hannam's emails and the regulator did not remove his "fit and proper" status, required for working in London's financial sector.
Hannam, who resigned from his job in 2012 to fight the allegations, argued the emails were too imprecise to constitute insider information - and might even have been inaccurate.
The case laid bare the ease with which bankers handle potentially market-moving information. The FCA accused him of having a "relaxed and improper" attitude and a "casual" attitude to disclosure beyond that allowed and necessary to do his job.
But lawyers said the case was a timely reminder that the FCA, born last year with fresh powers to enforce market conduct, should not be overly hasty in its attempts to improve market integrity in London.
"Ian Hannam is one of the few prominent City (of London) figures who have challenged an FCA fine," said Simon Morris of London law firm CMS. "While he didn't succeed others have, and this gives the FCA the important reminder that all its decisions must be of sufficient quality to sustain judicial scrutiny."
Hannam, who was not immediately available for comment, has until August 7 to pay the fine in full.
($1 = 0.5859 British Pounds) (Editing by Clare Hutchison and Mark Potter)