We don’t yet know the number of NHS staff who have lost their lives in the battle against Covid-19. On Wednesday, Dominic Raab put the figure at 69, but the true figure is considered to be far greater. The Guardian has recorded more than 100 deaths so far, but even this is an underestimate because not all deaths are in the public domain.

These deaths are not “natural” casualties of the coronavirus pandemic. In fact, they may be the result of a failure in the government’s duty to care for NHS staff, which is why it is vital it is properly investigated under the law.

Since the pandemic reached the UK, we have heard countless reports of doctors and nurses raising the alarm over the lack of personal protective equipment (PPE) when treating Covid-19 patients. Abdul Mabud Chowdhury was one of those who raised the alarm, and he has since tragically died. He worked as a consultant urologist at the Homerton hospital in east London. In March 2020, in a Facebook message to Boris Johnson, he called urgently for PPE for frontline NHS staff and the need for testing.

Josiane Zauma Ebonja Ekoli was a nurse at Harrogate and District NHS Trust on a Covid-19 ward before becoming ill. She died in a hospital she had previously worked in. Her daughter Naomie reported her mother’s description of the “poor” availability of PPE equipment for nurses and doctors. Naomie has called on the government to get better PPE for NHS frontline staff: “The least they could do is up the PPE so they can make sure it doesn’t happen to another family.”

How many of these deaths could have been prevented had sufficient PPE been provided to NHS workers? And if there is a lack of PPE, how did this happen? The health secretary, Matt Hancock, says the biggest challenge is “one of distribution rather than one of supply”. Should more have been done to meet this challenge, and if so what? Does the government have a legal duty to do more to protect the lives of healthcare workers?

The World Health Organization has prepared guidance on the “rational use” of PPE. It states that preventative measures are key to stopping the spread of the disease. Those most at risk are those in close contact with infected patients. The guidance makes recommendations for optimising the availability of PPE, but there is no transparency over whether the UK is putting them into practice.

There must be investigations into the individual deaths of NHS workers, out of respect to them, and also so that future deaths can be prevented. The evidence appears to be that the government has failed to protect them from risk to their lives, and if that is the case then an investigation will be required by law.

Article 2 of the European convention on human rights (which is not part of the EU) provides that not only must states not take life, they must protect it as well, taking measures to provide that protection for those at risk. The state is also under a duty to ensure there are appropriate systems and regulatory frameworks in place to protect individuals from risk to their lives. If there is evidence that this has not happened, there is also a procedural duty to initiate an effective public investigation into the deaths and the circumstances in which the obligation to protect lives may have been violated.

If this government has failed to involve itself in the EU’s bulk-buying scheme for PPE and other health equipment, or if it has failed to implement the WHO guidance on optimising the PPE that is available, and failed to put in place sufficient procedures to distribute lifesaving PPE, then it will have failed the frontline workers it has a legal duty to protect.

No doubt in some cases, the lack of PPE will have allowed the virus to spread from patients to staff. Several bereaved family members have expressed their belief that their loved ones caught the virus at the hospitals where they worked because of a lack of PPE.

A number of legal forums can investigate deaths in such circumstances. Section 1 of the 2009 Coroners and Justice Act requires a senior coroner to conduct an investigation into a death if there is reason to suspect, among other things, that the deceased died of violent or unnatural death. Although the chief coroner has produced guidance stating that Covid-19 can be a natural cause of death, which is not on its own a reason to refer it to a coroner, once issues of systemic failure are also raised then the need for inquests might well be essential to satisfy Article 2 of the European Convention.

It may also be necessary for a public inquiry under the 2005 Inquiries Act, as in the case of the Grenfell disaster, to investigate possible systemic breaches that have contributed to the deaths of NHS workers.

In the words of Dr Chowdhury, healthcare workers have a “human right like others to live in this world disease-free with [their] family and children”. The state has a duty to protect their lives as it does to all its citizens. Their deaths should not be treated as a regrettable necessity. If they have been failed then there should be full investigation to uncover the extent of the mistakes, so more lives are not lost in the future.

• Stephen Cragg is a barrister specialising in public law, healthcare law and human rights at Doughty Street Chambers. Emily-Jade Defriend is a solicitor specialising in human rights, inquests and public inquiries at Bindmans LLP