The U.K Financial Services Authority’s determination to get tough on insider dealing continues. Last week it sought to extradite a suspect for the first time, now it has raided addresses and made arrests in what it says is its biggest ever operation against insider dealing.

In its first joint operation with officers from the Serious Organized Crime Agency, a branch of the Police, the FSA made dawn raids on 16 addresses in London and across the country. Some 143 FSA staff were involved.