The death was revealed in data announced by health chiefs on Thursday as it was reported that 135 more people had lost their lives in the UK in all settings. The news came as Sheffield children’s hospital confirmed that a child died on Monday after being admitted in a critical condition. The hospital, which has not confirmed the age of the child, said they had tested positive for Covid-19 but the cause of death had not been determined. Previously, the youngest victim with no pre-existing health problems was believed to be Ismail Mohamed Abdulwahab, from Brixton in south London, who died in March aged 13 years. A study led by Imperial College London, and published earlier this month, revealed the condition to be distinct from Kawasaki, a rare but occasionally fatal disease. Researchers said they could not be certain this new illness was caused by Covid-19, but said 45 of the 58 children involved in the study had evidence of current or past coronavirus infection.