Sorry to rain on the parade, but the FSA made things rather worse for bankers, actually. Before that, the burden of proof for insider trading was so onerous that even the most apparently egregious (alleged) act went unpunished: think Archer and Anglia:
http://en.wikipedia.org/wiki/Jeffrey_Archer#Allegations_of_insider_dealings
The number of steps to prove ITrading were numerous and each had to be ticked off: if one wasn't, there wasn't a case to answer.
IIRC from my FSA training a while back, there was a single case proven in 20 years. May be mistaken
The UK Act brought in market manipulation, summarised nicely here.
Shows some examples of successful prosecutions.