Serco, the private company that provides GP out-of-hours services in Cornwall, received an unannounced inspection of its head offices not long after it registered with the CQC in April.

A CQC spokesman said that as part of CQC registration, all out-of-hours providers would be inspected. However following concerns raised by local people and information gathered during the registration process, the CQC decided to ‘prioritise’ Serco’s inspection, the spokesman said.

He added that CQC investigations following Serco's registration had identified a 'general discontent' within the provider and the inspection was a 'responsive' one.

Dr Gareth Emrys-Jones, a retired BMA council member and the former chair of the GP out-of-hours co-op that was replaced by Serco, told The Guardian that he had approached the CQC with concerns.

He said: ‘I have been approached by a significant number of people representing all classes of employees at Serco who felt unable to whistleblow directly but who perceived the service to be unsafe because of a lack of clinicians and inadequate cover for the needs of the patients of Cornwall.

‘They have cited incidents where it appears that data has been altered in order to achieve compliance with quality standards that they knew had been missed. These related to an extended time period and were not one-off incidents. I was concerned for the staff and for the service because if the allegations are true it would have serious implications.’

The CQC spokesman said its inspection of Serco was almost complete and that following its completion the CQC would issue a report on Serco. ‘If there are any issues arising from that we will be requiring action thereafter,’ the spokesman added.

A Serco spokesman said: ‘The Serco Cornwall GP out-of-hours contract was found to be and reported as one of the best performing such contracts in the UK by The Primary Care Foundation, as part of its National Benchmarking Exercise.

‘We are fully committed to providing the best possible care for patients. Since the out-of-hours service started, Serco has not scored less than 95% in the monthly patient satisfaction survey and over 86% of patients rate the service either excellent or good.

‘An independent audit commissioned by Cornwall PCT found that there was no substance to any allegations of altering figures or manipulating data. The auditor tested the data logged by Serco against key performance indicators, national quality requirements and complaints and incidents and found that the information Serco reported to the PCT was accurate.’

‘A substantial number of the allegations considered by The Guardian have been raised before, fully investigated by a number of independent bodies and found to be false and without foundation.’

Bridget Sampson, director of primary care for NHS Cornwall and Isles of Scilly, said: ‘We are disappointed that rumours still persist around the quality of service provided by Serco. Patient surveys show a high level of satisfaction with the service and an independent audit did not find any evidence of data being changed.

‘We are confident the service is adequately resourced and meeting the required national quality standards. The contract provides a value for money, high quality service for patients, with equitable access to GP appointments out-of-hours.’