Four men, including one of the most senior bankers in the City, were today charged with insider trading by the leading finance watchdog.
The Financial Services Authority (FSA) says that Martyn Dodgson, Andrew Hind, Benjamin Anderson and Iraj Parvizi conducted a long-running conspiracy to trade on inside information between November 2006 and March 2010, netting profits of £3m.
Mr Dodgson is the most high-profile name involved in the case and probably the best-known City figure to be charged with insider dealing.
As a high-flying managing director at Deutsche Bank, he was regarded as one of the top bankers in London with impeccable sources in both politics and finance.
Before the scandal broke he was advising the Treasury on its investment in the bailed-out Royal Bank of Scotland and Lloyds. He had previously worked for other top banks including Cazenove and Lehman Brothers.
All four men were bailed to attend Westminster magistrates' court on 19 October. They face prison sentences of up to seven years as well as bans from the City if found guilty.
The FSA describes the investigation, dubbed Operation Tabernula, as its largest and most complex insider dealing case to date. The watchdog has pledged to clamp down on insider trading, a practice it regards as rife but which is notoriously difficult to prove.
In this instance the allegation is that the conspirators were "front running". That is, taking large positions in stocks ahead of clients that are known to be buying the same stocks.
Five other men were arrested in connection with the inquiry but have not yet been charged. These men include Julian Rifat of the Mayfair hedge fund Moore Capital and Clive Roberts of Exane BNP Paribas.
The FSA said: "A number of individuals remain under investigation."
Mr Dodgson and Mr Hinds both live in north London. Mr Anderson lives in Surrey and Mr Parvizi in Spain.
A lawyer for Mr Parvizi said he "emphatically denies the charges and is determined to clear his name".
A lawyer for Mr Dodgson did not return a call seeking comment.
It is thought the FSA case centres on insider share trading in dozens of companies, including many household names such as Barclays and National Express.