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.
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Mixed fortunes across the UK tomorrow. Still breezy across the north.
The Labour leader said socialist politics would not be put "back in a box" as he appeared on stage at the festival.
There are reports that at least some MPs and Lords have been left unable to access their emails as a result of the attack.