NHS England has been given more time to submit an independent investigation into the killing of two men by another patient on a hospital ward.

HSJ revealed in March that Ken Godward, 76, and Roger Lamb, 79, were beaten with a walking stick by 70 year old Harry Bosomworth at Leeds Teaching Hospitals Trust in 2015.

Mr Bosomworth had a history of paranoid schizophrenia and hospital staff stopped his antipsychotic medication despite repeated warnings from his stepdaughter.

More than three years after the attack, there has not been an inquest into the deaths of Mr Godward and Mr Lamb. An independent investigation by NHSE has been mired in difficulty and delayed due to a dispute between the trust and NHSE investigators over the terms of reference.

An earlier report identified multiple failings by the trust. It said Mr Bosomworth’s mental healthcare had been secondary to his physical care and staff on the ward in St James’s University Hospital, where he was being treated, had no formal training in dealing with challenging patients.

The ward reported 46 violent incidents and episodes in the months leading up to and after the attack.

Leeds senior coroner David Hinchliff was told in January the NHSE investigation was nearly complete and a final copy would be ready by February.

However, NHS England confirmed at that time that there was no draft report and no timescale for when it would be produced.

This prompted the coroner to impose a deadline of 1 May on NHSE but this has been missed.

Mr Hinchliff has now retired, but his successor has extended the deadline and committed to holding an inquest soon after.

Senior coroner Kevin McLoughlin said: “After granting the requested extension, I fully expect to have the report by 21 May. At that point, I will review the file in its entirety and identify a court date to suit the availability of the witnesses who will be required to give evidence in person.”

An NHSE spokesman said: “Independent investigations require close working with the families and organisations. Given the complexities and sensitivities, timescales cannot always be accurately predicted at the outset but any revisions are made in consultation with all those involved.”