Costs include the staffing of a team to meet the inquiry's requests for data and information, as well as legal representation for EPUT and former and current employees involved.

The remit of the inquiry, which is focused on the deaths of mental health inpatients in Essex between 2000 and 2023, has been extended to those who have died within three months of discharge or consultation for admission, including those on end of life and dementia care.

EPUT has accessed thousands of data sources over 24 years to provide information to the inquiry.

Trevor Smith, chief executive of Essex Partnership University NHS Foundation Trust, said: ‘As the inquiry progresses, there will be many accounts of people who were much loved and missed over the past 24 years, and I want to say how sorry I am for their loss.

‘I apologise for any previous delays in providing information to Baroness Lampard and her team – we are committed to supporting the vital work of the inquiry and are investing a forecasted £30m to significantly strengthen resourcing and ensure we meet the needs of everyone involved while continuing to care for our patients.'