Southern Health faces Connor Sparrowhawk drowning charges
An NHS trust is to be prosecuted over the drowning of an 18-year-old patient at one of its facilities, the BBC has learned.
Connor Sparrowhawk suffered an epileptic fit while in a bath at Slade House in Oxford in July 2013.
Southern Health NHS Foundation Trust eventually admitted responsibility and offered his family compensation.
The Health and Safety Executive (HSE) told the BBC it will now prosecute the trust.
Following the announcement, Mr Sparrowhawk's mother Sara Ryan said: "I still feel really sad about it.
"I just feel we've been put through the mill. We have been treated appallingly and a young man should be doing whatever he would be doing right now.
"He should never have died."
The HSE said it was prosecuting the trust "under Section 3 of the Health and Safety at Work etc Act 1974 following its investigation into the death of a patient under its care".
A jury-led inquest in October 2015 found that "failings" by trust staff contributed to Connor's death.
The trust's boss Katrina Percy resigned in October amid public pressure.
Slade House closed in 2014 and the building is being transferred to Oxford Health NHS Foundation Trust.
Andrew Smith, the former MP for Oxford East who is not standing at the next election, said: "I was pleased to learn this news just as my time as MP was ending."
Southern Health provides mental health services to patients across Hampshire, Dorset, and Oxfordshire.
It is also facing prosecution over alleged failings at Melbury Lodge, Royal Hampshire County Hospital, where a patient sustained serious injuries during a fall from a low roof.
Southern Health Timeline
July 2013 - Connor Sparrowhawk, 18, drowns after an epileptic seizure at Oxford unit Slade House. An inquest later rules neglect contributed to his death
11 December 2015 - The BBC reveals details of a leaked Mazars report which highlights a "failure of leadership". Health Secretary Jeremy Hunt says he is "profoundly shocked"
17 December 2015 - The report is officially published and shows out of 722 unexpected deaths over four years, only 272 were properly investigated
6 April 2016 - The Care Quality Commission (CQC) issues a warning notice to significantly improve protection for mental health patients
29 April 2016 - A full CQC inspection report is published which says the trust is continuing to put patients at risk
30 June 2016 - Following a review of the management team competencies, it is announced that Katrina Percy is to keep her job
29 July 2016 - The BBC reveals the trust paid millions of pounds in contracts to companies owned by previous associates of Ms Percy
30 August 2016 - Ms Percy announces she is standing down as chief executive, but is staying on in an advisory role
19 September 2016 - Interim chairman Tim Smart resigns after admitting he created a job for Ms Percy
7 October 2016 - Ms Percy resigns completely from the trust
13 December 2016 - A CQC report, the culmination of a one-year inquiry, says investigations into patient deaths are inadequate
16 March 2017 - All the non-executive directors resign from trust