More than 20 dawn raids were carried out by the Financial Services Authority last year as the watchdog continued its use of visible enforcement, a law firm says.
Reynolds Porter Chamberlain said the increase in "more conspicuous and heavy handed" enforcement exercises since the start of the credit crunch moved the watchdog closer to the activities of US Securities and Exchange Commission.
According to RPC, the FSA averaged more than six dawn raids each calendar year from 2005 to 200. After the credit crunch this rose to an average of 29 raids a year from 2008 to 2011.
RPC regulatory partner Steven Francis said: "Most FSA dawn raids relate to suspected insider dealing, which the FSA has been clamping down on following criticism for letting too much criminal activity continue unchecked.
"The raids are also designed to send a very powerful message to the broader market. A lot of time, preparation and money go into every dawn raid so this is a really significant increase in activity by the FSA."
However, RPC noted a dip in number last year - dropping from 36 raids in 2010 to 21 in 2011.
Francis said: "The million dollar question is whether these highly visible raids are fundamentally changing people's behaviour and reducing insider trading, or whether the FSA's detection techniques are becoming more effective."
The law firm also said dawn raids can prove more expensive than a more conservative approach to enforcement and its use could be questioned on a cost basis.
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