Bosses of a scandal-hit health board have admitted they didn't know how serious the issues in maternity services were until they read a damning report into them.
Giving evidence to the Welsh Assembly's health committee, the Chief Executive of Cwm Taf Morgannwg, Allison Williams said that while she signs off on all complaints, she only saw what people wanted her to see.
Ms Williams, who's been in charge of the health board since 2011, said: "The extent of the feedback from the families was a shock to me." She added: "this is the most difficult thing I have ever come across in my career" and that the failings "go right through the organisation".
Dawn Bowden AM sought assurances that the health board is actually learning lessons. She said that when she met with with families affected they said their concerns appeared not to be taken seriously.
The health board says new measures have been put in place to ensure complaints are dealt with better in future.
Health board chair, Prof Marcus Longley said: "The board was aware of many of the issues that we're talking about now," but said that they weren't resolved. He added: "We didn't appreciate the full extent of the issues."
Questions were also asked of what was described by Plaid Cymru's health spokesperson Helen Mary Jones as the 'toxic culture' within the health board. The recent royal college report identified that staff felt unable to raise concerns about care and safety through fear of disciplinary action.
Allison Williams said that it builds up over time and that to answer how it built up and what was known when was 'a difficult question to answer.'
The evidence session follows the publication of a damning report into maternity services, which uncovered systematic failures in care and governance. The service has since been put into special measures and an independent review team assembled to look back at cases back to 2010.
Concerns were initially raised when it was discovered the health board was under-reporting serious incidents, including the deaths and serious injuries of babies and mothers.