With this latest Ancestry update, England and Wales Death Index, 1989-2022, has 6,947,083 entries.
Scotland and Northern Ireland, Death Index, 1989-2022
now has 897,449 entries.
A search provides name, gender, age, birth date, last residence (town), postal code district and death date. The source is not specified but appears to be compilations from unofficial records, such as funeral homes and newspapers, from GreyPower Deceased Data and Wilmington Millennium, West Yorkshire. I estimate it covers about half the deaths occurring.