Business Green: Gordon Brown has this afternoon announced that the Labour Party will enter into formal talks with the Lib Dems and that he will step down as Labour leader before the Party’s annual conference in September. In a bold move that raises the prospect of a "rainbow coalition" government, including Labour and the Lib Dems, as well as other "progressive" parties such as the SNP, Plaid Cymru, the SDLP, the Alliance and the single Green MP Caroline Lucas, Brown said he would "facilitate" formal …