Two fresh investigations are being launched into Cornwall's out of hours doctors.

One will look at care standards, after a report revealed some were working 13 hour shifts or did not have proper training.

Another will focus on why call-out records were changed.

When the Primary Care Trust carried out an earlier audit, it had said that could not happen.

Serco boss Paul Forden says there is always a good reason: "If a patient is due to go to a clinic at 7 o'clock in the evening and they arrive at 9pm, what we do is we say to the PCT, there are two reports here; one shows the due time, which was 7 o'clock, and the other shows the actual time of arrival.

"What we don't do is double-check every single piece of data because I'd employ an army of administrators. So what we do is where we believe there are potential inaccuracies, we will then look and say, actually, was that the correct thing to do?"

The Primary Care Trust insists it will get to the bottom of why the changes were missed, adding that the CQC were directed to look at specific call records by the members of staff who contacted them, whereas its audit relied on random sampling.

Medical Director Dr Shelagh McCormick said: "We need to understand what's happened here and at the moment this is unexplained. I think until we've understood it, it's difficult to comment any further on that. Obviously we will be working to assure ourselves and to assue the public that this in no way compromises patient safety.

"We want to work with Serco to help improve any issues that have been found. We had already started that process when we first became aware that there were some problems. We intend to use the CQC report as a jumping off point so that we can improve the service".