The families affected by the “horrific” crimes of serial killer nurse Lucy Letby deserve to get answers at a statutory inquiry, said Health Secretary Steve Barclay as he published its terms of reference.

In August, Letby, 33, of Hereford, was sentenced to 14 whole life orders after she was convicted of the murders of seven babies and the attempted murders of six others, with two attempts on one of her victims.

The offences took place at the Countess of Chester Hospital’s neonatal unit, where Letby worked, between June 2015 and June 2016.

One of the country’s most senior judges, Lady Justice Thirlwall, will lead the inquiry which is said to be “currently setting up its infrastructure at pace so that it can begin its investigations”.

The inquiry will cover three broad areas, it was announced on Thursday.

Firstly, the experiences of the parents of the babies who featured in the 10-month trial that Letby faced at Manchester Crown Court.

Secondly, the conduct of clinical and non-clinical staff and management as well as governance and escalation processes in relation to concerns being raised about Letby and whether these structures contributed to the failure to protect babies from her.

Thirdly, the effectiveness of governance, external scrutiny and professional regulation in keeping babies in hospital safe, including consideration of NHS culture.

Mr Barclay said: “Losing a child is the greatest sorrow any parent can experience, and I cannot begin to imagine the hurt and suffering experienced by the families affected by Lucy Letby’s horrific crimes.

“We have a duty to get them the answers they deserve, to hold people to account where they need to be, and to make sure lessons are learned.

“These terms of reference have been agreed following engagement with the families, and I am confident Lady Justice Thirlwall will ensure their voices are heard as the inquiry gets under way.”

As part of its probe into the conduct of those working at the hospital, the inquiry will look at whether the police and other external bodies should have been informed sooner of suspicions about Letby.

It will also focus on the responses to concerns raised about the nurse from those with management responsibilities within the trust, as well as investigating whether the trust’s culture, management and governance structures and processes contributed to the failure to protect babies from her.

The procedure and conduct of the inquiry will be directed by Lady Justice Thirlwall.

The Government’s publication of the terms of reference states: “The priority is to conduct a thorough inquiry as swiftly as possible.

“The length and timing of the hearings and where they take place will depend on the extent and nature of the live evidence that is required and upon the actions of the police and Crown Prosecution Service.”

The inquiry chairwoman will provide a final report to the Health Secretary and make recommendations as she considers appropriate, it added.

Irwin Mitchell lawyer Tim Annett, who represents a number of the affected parents, said: “All our clients want is for no stone to be left unturned in fully establishing how Letby was able to commit the most heinous crimes.

“We welcome the terms of the investigation which will hopefully provide families with the answers they deserve, although our clients also hope that it will be possible to investigate the full extent of Letby’s unlawful activities.

“While nothing will ever make up for the losses suffered by the families, we’re determined to working with the inquiry to ensure it’s as effective as possible in producing robust recommendations to minimise the risk of similar events in the future.”