Health and social care inspectorate body the Care Quality Commission said they were "appalled" by the Serious Case Review into the deaths of five residents of Orchard View care home, and admitted they did not act quickly enough.
They were criticised by the coroners report into the death for giving the home a "good" rating a year before shutting it down.
Chief Inspector Andrea Sutcliffe said the blame for the "sub-optimal" care lay with those working in the home.
I was appalled by the descriptions of what had happened at Orchid View. Today’s Serious Case Review once again shows what a truly tragic situation this was and my thoughts remain with the people who suffered such awful care and with their families.
The Serious Case Review shows the primary responsibility for these failings rests with the people providing services at Orchid View, together with their owners Southern Cross.
Ms Sutcliffe admitted the Care Quality Commission missed early warning signs, and did not act quickly or strongly enough. She said:
At CQC we made a commitment to take a long, hard look at our role, make sure lessons were learned - and most importantly - turn those lessons into action.
We know from our own review that we did not fulfil our purpose of making sure Orchid View provided services to people that were safe, compassionate and high quality.
More top news
Defence saving plans raise "serious doubts" over the Ministry of Defence's ability to pay for new equipment, including warships and planes.
One firefighter has been killed and more than 700 homes destroyed in the 404-square-mile Thomas Fire.
Theresa May has said there is "no place in our politics" for intimidation after Tory Brexit rebel MPs received death threats and abuse.