Martha's rule, a way for families to seek an urgent second opinion if they are concerned about the care their loved ones receive, will be rolled out across all English hospitals delivering acute or short-term treatment.
The telephone helpline, the result of a campaign by the parents of 13-year-old Martha Mills who died after serious failings in her care, has been piloted in 143 hospital sites in England since April 2024.
Figures from NHS England show that since then there have been almost 5,000 calls, resulting in 241 potentially life-saving interventions.
Martha's mother, Merope Mills, welcomed the expansion on what would have been her daughter's 18th birthday but wants UK-wide access.
She told BBC Radio 4's Today programme the new figures proved the need for the rule and "a different, more equal kind of doctor-patient relationship".
