An NHS trust’s lack of honesty caused “unnecessary pain and further distress” to a family who had already suffered from the tragic and avoidable death of a baby boy, the health service ombudsman has said in the latest scathing verdict on the defensive culture within the health service.

Change was needed “from the ward to the board” said Dame Julie Mellor as she upheld three of four complaints made by relatives of Joshua Titcombe against University Hospitals of Morecambe Bay NHS foundation trust.

Mellor had already upheld a complaint from James Titcombe, Joshua’s father, against the NHS’s now-defunct strategic health authority in north-west England, over how it investigated events at the trust.

Cumbria police are still investigating Joshua’s death. He was born at Furness general hospital, part of the trust, in October 2008 but was transferred to hospitals in Manchester and then Newcastle where he died from pneumococcal septicaemia, just nine days old.

The trust later confirmed that Joshua would have had an excellent chance of survival if opportunities to diagnose and treat his infection had not been missed.

In remarks that echoed the fallout from Sir Robert Francis’s report on the scandal at Stafford hospital last year and other incidents, the ombudsman said that the relationship between the Titcombe family, whose identities are anonymised in the report, and the Morecambe Bay trust was “a further sad example” of the need for cultural change.

“Hospitals and other healthcare providers have a duty to patients and their families to investigate their concerns properly. In these cases the trust failed to be open and honest about what went wrong and this caused the complainant and his family further unnecessary distress at a very difficult time,” said Mellor.

“When serious untoward incidents happen there needs to be an independent investigation which looks at the root cause of the complaint and the role of human factors such as people and the organisation’s culture. We expect all service providers to adopt this approach to help them understand why mistakes happen and help improve services for everyone.”

Mellor said hospital boards should “reward staff who seek and respond well to concerns and complaints, including acknowledging mistakes.” She also apologised for a decision in 2010 by her predecessor, Ann Abraham, not to investigate a complaint from Titcombe. “We recognise that had we investigated, the family might have had answers to some of their questions regarding what happened to their baby sooner than they did. We are sorry for the impact this has had on the father and the baby.”