The denial came after The Sunday Times said it had obtained documents spelling out restrictions on the way investigations are done and requiring teams behind them to discuss final reports with NHS England.

Professor Marian Knight, who leads production of the Mothers and Babies Reducing Risk through Audits and Confidential Enquiries report, known as MBRRACE, told the newspaper restrictions placed on audits had ‘limited our ability to make a difference, to get our messages through and to drive change'.

An NHS spokesperson said: ‘Neither NHS England nor any other body alters the data or factual findings in national clinical audits in any way and authors retain control of the analysis and conclusions.

‘Clinical audits are independent evidence-based reports to help the NHS improve services for patients and families and we work with auditors to ensure their recommendations are clear and can be implemented across the NHS to improve care.'