The family of a 13-year-old girl who died of a sepsis infection are calling for patients and their loved ones to be given the right to ask for an urgent second opinion.

Martha Mills died two years ago when doctors failed to spot and treat her condition early enough.

Speaking on BBC Radio 4’s Today programme, Martha’s mother, Merope, said she thinks about her daughter’s last days all the time, and “what could have happened to change the outcome.”

She wants hospitals around the country to bring in “Martha’s rule” – which would give parents, carers and patients the right to ask for an urgent second opinion from a critical care team at the same hospital – if they have concerns about their current care.