The Financial Services Authority (FSA) has secured a high-profile prosecution against a former Dresdner investment banker for insider dealing, in the latest crackdown on market abuse by the City regulator.

Christian Littlewood has been sentenced to three years and four months in prison for eight counts of insider trading which occurred between 2000 and 2008 during his employment at Dresdner and most recently Shore Capital. During this time he accrued a total of £590,000 in relation to the charged offences.

The sentence was handed down by His Honour, Judge Leonard QC in Southwark Crown Court yesterday (2 February). Littlewood's wife, Angie Littlewood, and family friend Helmy Omar Sa'aid also pleaded guilty to insider dealing. Angie Littlewood was sentenced to 12 months in custody suspended for two years, while Sa'aid was sentenced to two years and ordered to pay £640,000.

The case marks the first successful criminal prosecution by the FSA against a banker still working in the City at the time of arrest. It also marks the longest jail sentence handed down in this type of case.

FSA managing director of enforcement and financial crime Margaret Cole (pictured) said: "This was a case of systematic abuse by an approved person of their privileged position in the market – we are determined to stamp out such abuse. Our tough, coordinated approach to insider dealing and our commitment to taking on difficult criminal prosecutions has really begun to pay off."

The verdict comes after Neil Rollins, a former manager at waste management company PM Onboard, was last month sentenced to 27 months' imprisonment for five counts of insider deal and four counts of money laundering following an FSA prosecution.

The recent convictions underline the current push by the FSA to bolster its credibility by taking a more aggressive stance in pursuing market abuse cases. The FSA, which is set to effectively be split into two bodies as part of Government plans to overhaul City regulation, is currently prosecuting another 12 individuals for insider dealing.

Clifford Chance litigation partner Luke Tolaini told Legal Week: "This is a success for the FSA, there is no doubt about it. This is something that they are obviously focusing on strongly and Littlewood received a proper sentence. The only question that arises now is: can they do it frequently enough to build up a credible deterrent? They will have to keep bringing cases in order to do this."

Littlewood was advised by Russell Jones & Walker business crime and regulation partner Jeremy Summers with Matrix Chambers' Lord Ken Macdonald QC instructed as counsel.

Hickman & Rose fraud partner Andrew Katzen advised Angie Littlewood with 7 Bedford Row's Richard Latham QC instructed as counsel. Sa'aid was advised by Luton-based Mitchell Solicitors' Dominique Mitchell-O'Neill with David Gibson-Lee of Bell Yard Chambers instructed as counsel.

The FSA instructed Nicholas Dean QC at 7 Bedford Row in addition to its in-house legal team.