London’s ambitions to attract foreign-owned mining companies have suffered a sharp blow with the announcement by Bumi Plc of an inquiry into alleged irregularities at subsidiaries, just days before a clamp-down on listing rules.

The Financial Services Authority (FSA) will publish proposals next Tuesday designed to protect investors and ease concerns that London-listed companies such as Bumi, an Indonesian coal venture co-founded by financier Nat Rothschild, are diluting standards of corporate governance.