Bolton NHS Foundation Trust said it received information about an initial audit about potential discrepancies in the way the trust coded mortality information in 50 cases between March 2011 and April 2012.

BBC: Royal Bolton Hospital

In his letter sent last month, Mr Dalziel recognised Mr Johnson's awareness of the audit's initial findings.

BBC: Grampian fire chief concerns for Highlands fire service

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