Only half of the NHS’s new regional health service bodies will be fully ready to start work when the changes come into effect today.
Just 106 of the 211 Clinical Commissioning Groups (CCGs) are "fully authorised", said NHS England.
The new groups are led by GPs and other clinicians who will take on responsibility for commissioning local hospital, community health and mental health services.
More top news
The prime minister was shouted at as she left the scene of the tragedy in which at least 79 people died.
Father-of-six Makram Ali, 51, was already receiving medical treatment as the attack unfolded. He died from multiple injuries, police say.
A review of how police and security services dealt with the latest terror attacks in the UK is to be launched, Amber Rudd has announced.