In addition, we recommend that the PCAOB make this in-depth analysis of audit failures an on-going function of the Board, in order to ensure that changes in policy and oversight practices are adopted in a timely fashion to address correctable weaknesses in the audit process.

FORBES: Why No Warnings? Investors Press Audit Regulator

But Mr Thomas said the initial investigation had "identified a number of questions and concerns which I now consider warrant further in-depth audit investigation".

BBC: Wales politics