Health Secretary Jeremy Hunt has ordered a review into how deaths are investigated by NHS trusts following the report into Southern Health.
The independent investigation report by NHS England into Southern Health has been published with a number of recommendations for the trust to review its procedures into how deaths of those who have received its care are investigated.
The probe into Southern Health, which showed the trust failed to probe the deaths of more than 1,000 people since 2011, was launched after concerns were raised following the death of Connor Sparrowhawk.
The 18-year-old drowned following an epileptic seizure while a patient at a Southern Health hospital in Oxford in 2013 and a previous independent investigation found that his death had been preventable and an inquest jury found neglect by the trust had contributed to his death.
In a written ministerial statement, Mr Hunt said: "The report describes a lack of leadership, focus and sufficient time spent in the trust on carefully reporting and investigating unexpected deaths of mental health and learning disability service users.
"The report found that there had been no effective, systematic management and oversight of the reporting of deaths and the investigations that follow.
"I am determined that we learn the lessons of this report, and use it to help build a culture in which failings in care form the basis for learning for organisations and for the system as a whole."
Mr Hunt announced that the Care Quality Commission (CQC) will launch a focused inspection of Southern Health in the New Year as well as carry out a wider review into the investigation of deaths in a sample of all types of NHS trusts.
There will also be a learning disability and mortality review to help analyse the issue with further support being offered to medical directors, Mr Hunt said.
Southern Health is a mental health trust providing services to 45,000 people across Hampshire, Dorset, Wiltshire, Oxfordshire and Buckinghamshire.
The NHS England investigation was carried out by the audit firm Mazars and looked at patients who had received some care from Southern Health in the 12 months prior to their death in the period between April 2011 and March 2015.
The report, which was leaked to the BBC last week, showed that of the 1,454 unexpected deaths, only a total of 195 (13%) were treated by the trust as serious incident requiring investigation (Siri).
The report states in its key findings that: "There was a lack of leadership, focus and sufficient time spent in the trust on carefully reporting and investigating unexpected deaths of mental health and learning disability service users.
"Despite the board being informed on a number of occasions, including in representation from coroners, that the quality of the Siri reporting processes and standard of investigation was inadequate no effective action was taken to improve investigations during the review period."
The report states that 30% of all deaths (those reported as expected and unexpected) in adult mental health services were investigated while less than 1% of deaths in learning disability services were investigated and 0.3% of all deaths of older people in mental health services were investigated as a Siri.
A report summary adds: "It took Southern Health NHS Foundation Trust a long time to investigate a death. When an investigation did happen the quality of these investigations was not good."
Katrina Percy, chief executive of Southern Health NHS Foundation Trust, apologised for its failings and said it had changed its procedures for recording and investigating deaths.
She said: "We fully accept that our processes for reporting and investigating deaths of people with learning disabilities and mental health needs were not always as good as they should have been.
"We also fully acknowledge that this will have caused additional pain and distress to families and carers already coping with the loss of a loved one.
"We apologise unreservedly for this and recognise that we need to make further improvements.
"In the past, our engagement with families and carers of people who have died in our care has not always been good enough. Whilst we have already made substantial changes in how we approach this, we have more improvements to make."
She said improvements made include the setting up of a new central investigation team and improving analysis of inquest conclusions as well as the launch of a new system for reporting and investigating deaths which involves the family of the deceased.
Ms Percy added: "We fully accept a need to continue to make changes, and will work with our commissioners and regulatory bodies to make the improvements required. Our main focus continues to be ensuring that everyone who relies on the services we provide receives the best possible care."
She added: "In most cases referred to in the report, the trust was not the main care provider.
"The review did not consider the quality of care provided by the trust to the people we serve.
"National data on mortality rates confirms that the trust is not an outlier. We believe that Southern Health's rate of investigations into deaths is in line with that of similar NHS organisations."
Jan Tregelles, CEO of Mencap, said the failings at Southern Health were systematic of issues across the NHS.
She said: "For families affected by the review into deaths at Southern Health Foundation Trust, fundamental questions continue to remain unanswered - what caused the deaths of their loved ones and were the deaths avoidable?
"The Government and NHS must, as a matter of urgency, say how they will support every family to get answers about the death of their loved one."
She added: "A lack of understanding of learning disability and institutional discrimination have continually been mentioned in previous reports and reviews, and the Mazars Review raises similar issues.
"The Government and NHS England must act immediately to address the failures of care that have seen so many people with a learning disability tragically lose their lives within the health system."
Sue Rawlinson, whose daughter Nicki, 26, who had a learning disability, died at Barnet Hospital in north London in February 2012, said: "The NHS didn't take any responsibility until, with the support of Mencap, I forced them to investigate the death.
"It's an absolute disgrace the way my daughter died. Today's review is a timely reminder. The NHS must start treating the lives of people with a learning disability with the same value as anyone else's life."
The NHS regulator Monitor is to review the report to consider the recommendations in relation to national policy and to consider "as a matter of urgency" whether regulatory action is required.
The report will also feed into the National Learning Disability Mortality Review Programme which was announced in June.
Jane Cummings, chief nursing officer, said: "Openness, transparency, learning, improving and working with families should be the core tenets of the NHS, especially where things don't go right.
"We commissioned this report following concerns expressed by Connor Sparrowhawk's family, and we are grateful for their contribution to this publication.
"The report now demands further action from us and others, in particular that its findings should be shared across England to ensure that deaths are investigated properly.
"We have jointly committed to ensure that this and the other actions it sets out are taken."