In written evidence to the Health and Social Care Committee, the CQC said the move threatened the ‘safe space' between its proposed investigatory and regulatory arms.
The letter states: ‘We are committed to working with both HSSIB and DHSC to further explore approaches to this, but we are yet to determine whether there is a valid operational solution that can completely resolve this conflict.
‘This would pose an inherent reputational risk to us alongside a potential risk to patient safety on which we cannot take action.'
The DHSC told us it was committed to delivering the recommendations of the Dash review of the patient safety landscape published in July 2025 that found a fragmented, cluttered and overlapping patient safety system, including duplication between the HSSIB and CQC.
However, the CQC warned the transfer could challenge its ability to carry out its existing functions.
It argued its investigation function will hold information its regulatory function is unaware of and cannot act upon.
The CQC said its board would lack complete oversight and assurance of its investigatory arm's functions in relation to protected disclosure provisions despite being accountable for it.
It added there was a potential the two functions could face each other in court which it described as an ‘undesirable situation'.
