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A former senior investment banker and an accountant have been jailed for their part in the UK's "largest and most complex insider dealing investigation".

Former Deutsche Bank managing director Martyn Dodgson was sentenced to four and a half years in prison, the longest term for the crime in the UK.

Businessman Andrew Hind received three and a half years.

They were convicted on Monday of conspiring to "insider deal".

The sentences at Southwark Crown Court bring to a close the Financial Conduct Authority's (FCA) "Operation Tabernula" investigation which began in 2007.

The FCA described it as its largest and most complex insider dealing investigation. It said the offending was "highly sophisticated" and that the investigation was "demanding and time-consuming".

'Secret'

According to an FCA statement released following the convictions, Martyn Dodgson "sourced inside information from within the investment banks at which he worked, either through working on transactions himself or through being able to glean what his colleagues were working on".

He passed this inside information onto Andrew Hind who acted as a "middle man" and "effected secret dealing for the benefit of Dodgson and himself".

The FCA said the two men used elaborate strategies to keep their activities secret including using unregistered mobile phones and encoded and encrypted records.

The charges related to a period between November 2006 and March 2010. The regulator used five instances of insider dealing to prove its case, including ones related to Scottish and Newcastle in 2007 and BSkyB in 2010.

During this time Mr Dodgson worked for Morgan Stanley, Lehman Brothers and Deutsche Bank. The FCA described Mr Hind as a "businessman, property developer and a qualified chartered accountant".

It added: "Dodgson was an experienced and well-paid banker, well aware that what he was doing constituted a criminal offence and who conspired with Hind to abuse our market and to profit at the expense of the investing public."

The maximum jail term for insider dealing in the UK is seven years.

Five people have now been convicted as part of Operation Tabernula which was carried out in co-operation with the National Crime Agency.

Three other defendants were acquitted on Monday.