THE son of a retired property developer who killed his wife and then himself has criticised an under-fire NHS trust for not learning from mistakes in mental health care.

Joe Goswell, whose parents Roger, 66, and Susan, 63, died nearly nine years ago, said the manslaughter conviction this week of Matthew Daley for killing Donald Lock, 79, revived painful memories.

He said the Daley case proved Sussex Partnership NHS Foundation Trust had failed to learn lessons following his parents' deaths, despite recommendations made in the aftermath.

The trust's chief executive, Colm Donaghy, admitted this week, following the conclusion of Daley's two-week trial at Lewes Crown Court, that it had "got things wrong" in his case.

The Argus revealed Daley's mother had called the trust worried about her son the day before he killed Mr Lock but the concerns were not passed on to police.

The trust has announced an independent review of 10 killings involving patients known to the trust, including the cases of the Goswells and that of paranoid schizophrenic Daley.

Mr Goswell's mentally unwell father fatally stabbed his mother and clubbed her with a rubber-headed mallet at their gated bungalow in West Chiltington on December 23, 2007.

A four-day inquest in 2008 heard of a series of shortfalls by medical professionals and police in the weeks leading up to the couple's deaths.

Of the Daley case, Mr Goswell said: "We would have hoped that they would have learned from their mistakes, but clearly they haven't.

"We sometimes feel that, as children, could we have done something else to have helped our mother and father, but we were in the hands of doctors and medical professionals.

"We felt at the time that they knew best, and that wasn't the case with us."

Daley's trial heard examples of his violent behaviour before he killed Mr Lock and that at one point he was calling police so often about voices in his head they threatened to charge him with wasting police time.

Sussex Police was unable to answer several questions about its involvement with Daley by deadline yesterday but has said it will do so within a week.

Yesterday the minister of state for community and social care, Alistair Burt, told The Argus he was "deeply saddened" by the Daley case.

He added: "I would like to add my condolences to those of the Trust.

"I welcome the Trust’s determination to learn lessons in order to address the distressing issues behind this tragedy.”