The report conducted by Theemis includes a series of recommendations for Nottinghamshire Healthcare NHS Foundation Trust and NHS England.

Dr Jessica Sokolov, regional medical director at NHS England (Midlands), said: ‘It's clear the system got it wrong, including the NHS, and the consequences of when this happens can be devastating.

‘This is not acceptable, and I unreservedly apologise to the families of victims on behalf of the NHS and the organisations involved in delivering care to Valdo Calocane before this incident took place.'

In an open letter, Ifti Majid, chief executive of Nottinghamshire Healthcare, said: ‘As a trust, we should have done more to listen to families, colleagues and local partners while Valdo Calocane was using our services.'

Majid pledged a personal update in four months on the progress the trust has made on an improvement plan.

He said the trust had achieved the national target of seeing 95% of all people referred within 18 weeks, with every patient with severe and enduring mental illness like Calocane receiving a risk assessment and safety plan, and those transferring between services having a ‘much more robust discharge process'.

A joint action plan with Nottinghamshire Healthcare Trust has been published to address the recommendations of the Independent Homicide Investigation report.

Amanda Sullivan, chief executive of NHS Nottingham and Nottinghamshire ICB, said: ‘Extensive governance arrangements, including oversight from the ICB, regional and national NHS England teams, were set up following the attacks to monitor Nottinghamshire Healthcare NHS Foundation Trust's response to quality and regulatory concerns. Senior ICB leaders are part of this process, including the chief executive and chief nurse.'