Three men have been arrested as part of an investigation into suspected insider dealing, Britain's financial regulator said on Friday.

The three, all aged 38, were held on Thursday before being released on police bail, and four addresses in London were also searched, the Financial Services Authority said in a brief statement.

The FSA, which last year said it had adopted a more "intrusive and direct" style of supervision, has now carried out four sets of arrests in relation to suspected insider dealing since 2008.