The chair of an inquiry into more than 2,000 mental health-related deaths has said “we will never know” the true number of people who died.

The Lampard inquiry has started, examining deaths in NHS-run children and adult inpatient units in Essex between 2000 and 2023.

Baroness Lampard, who is leading the proceedings, said the investigation was “of extreme concern and importance”.

He warned that the number of deaths was likely to be “significantly higher” than the previously reported figure of 2,000.

Families unfurled banners and laid out posters and placards on the floor outside the Civic Center in Chelmsford ahead of the first session.

“The sad thing is that we can never have a definitive number of deaths,” Baroness Lampard said in her opening remarks. He said the scale was “extremely shocking”.

“We will never be able to say for sure how many people died,” he said.

Baroness Lampard also paid tribute to the “dedicated and tireless campaign” of the bereaved families.

• What is the Lampard Inquiry and what could it change?

The investigation was set to focus on the Essex Partnership University NHS Foundation Trust (EPUT), North East London Foundation Trust (NELFT) and pre-existing organisations.

It will not look at deaths in the community unless they occur within three months of discharge from a mental health unit, the patient has been assessed and has been refused a bed or they are referred for a bed. Be on the waiting list.

The first week of the inquest will hear opening statements from Baroness Lampard and legal representatives, before bereaved families read statements from next Monday.

It may take “a few years” for the full report of the investigation to be published.

Baroness Lampard said it would be “fair, objective, rigorous and balanced”.

EPUT chief executive Paul Scott said his thoughts were with those who had lost loved ones.

However, he disputed the figure of 2,000 deaths made public by the investigation.

He said this included deaths from natural causes, for example where some patients may have been transferred to hospital after suffering a heart attack.

Mr Scott said, “Patient safety is our absolute priority and we are committed to learning from the investigation’s work.”