Care Quality Commission inspectors were ordered to carry out a report by Health Secretary Jeremy Hunt following problems at Southern Health NHS Foundation Trust.
The trust’s chairman Mike Petter resigned “with great sadness” hours before the review was published.
“The trust has recently undergone a significant amount of scrutiny in some service areas and given the challenges it faces I feel it is appropriate for me to allow new board leadership to take forward the improvements,” he said.
Southern has been under intense scrutiny following the deaths of hundreds of patients, including 18-year-old Connor Sparrowhawk who died in 2013.
In October, a jury inquest ruled that neglect contributed to the death of Connor, who drowned after an epileptic seizure at Slade House in Headington, Oxfordshire.
CQC inspectors found that robust arrangements to probe incidents, including deaths, had not been put in place, resulting in “missed opportunities” to prevent similar events.
Effective measures to identify, record or respond to concerns about patient safety raised by patients, their carers, staff or by the CQC had also not been implemented.
And inspectors raised serious concerns about the safety of patients with mental health problems and learning disabilities in some of the areas inspected.
Concerns highlighted previously by the CQC of ligature risks had still not been properly addressed by the latest inspection, which was carried out over four days by a 22-strong team in January.
And in December, an independent investigation found Southern Health had failed to probe the deaths of hundreds of people since 2011.
The CQC inspection team spoke to patients, staff, carers, the trust board and whistleblowers.
They also reviewed patient records, serious incident reports, medication charts and policy and procedures.
Dr Paul Lelliott, deputy chief inspector of hospitals and lead for mental health at the CQC, said community mental health team staff lacked guidance on what to do when a patient fails to attend an appointment.
And he said some staff were still unsure of when and how to involve families following the introduction of a new system for reporting incidents and patient deaths.
He said: “I am concerned that the leadership of this trust shows little evidence of being proactive in identifying risk to the people it cares for or of taking action to address that risk before concerns are raised by external bodies.
“Along with partners, including NHS Improvement and NHS England, we will be monitoring progress extremely closely. We will be looking not only for evidence of improvements, but for evidence that this board is actively planning to protect patients in their care from the risk of harm.”
An action plan has been supplied by the trust and a further inspection will take place to check that improvements are being carried out.
Katrina Percy, chief executive of Southern Health, said the report sends a clear message to the leadership of the trust that more improvements needed to be made.
‘I want to reassure our patients, their families and carers that I am absolutely focused on addressing the CQC’s concerns and supporting our staff to provide the best care possible,’ she said.
Fareham MP Suella Fernandes added: ‘The resignation of the chairman is a significant recognition of the need for new leadership of the trust. It will be welcomed by many patients and relatives who have found it increasingly difficult to have confidence in the current board.’