David Prior, who was brought in to lead the Care Quality Commission in January after it faced criticism for failing to protect vulnerable patients, said that almost half of hospitals were now providing care which was either poor, or "not terribly" good.
He said the CQC had found 45 hospitals with problems dating back five years, and vowed that from now on regulators will take a "much clearer" approach in advising which hospitals should not be allowed to continue as they are.
We will be outside the system and the politics - we will have a huge role in the reconfiguration debate because we are independent.
More top news
A cool weekend ahead but looking dry for many with sunny spells.
Firefighters have warned residents in London that an ongoing blaze could spark the explosion of a gas cylinder.
From church bells to pageants on the Thames, festivities are prepared for the moment the Queen overtakes Victoria.