GPs have told the BBC their reputations have been "tarnished by incompetence" from the health watchdog.

The Care Quality Commission has been forced to apologise to hundreds of GPs for giving incorrect patient safety risk assessments.

A BBC investigation found serious errors in the calculations used by the CQC.

The British Medical Association is calling for the whole banding system to be withdrawn.

Around 60 practices have been taken out of the highest risk categories and four low-risk surgeries need early inspection.

John Flather, a GP in Hadleigh, Suffolk, said his practice had been incorrectly banded as high risk.

He said he was "totally disgusted by the process" and that a formal complaint had been made.

He told the BBC: "Our reputation, which has been built over many years, has been tarnished by incompetence that they purport to eradicate.

"If they had only given us a chance to view their ratings we could have pointed out their errors and avoided this mess."

Dr Chris Cullen, from Ipswich, said: "My practice was rated for highest risk despite being one of the very high achieving practices in the country.

"The CQC claim we gave flu jabs to 24% of our patients, in fact it was over 96%.

"Our true rating should be for lowest risk, but the CQC aren't interested and have not returned our calls."

Bad data

Practices were judged on 38 indicators of performance, ranging from how easily patients managed to get appointments to how good doctors were at picking up conditions such as dementia.

Practices were graded in six bands, with Band 1 being the highest concern, and Band 6 the least risky.

The majority were of low concern, but 11% were rated in the highest risk band.

The BBC discovered that for one indicator, whether patients were able to get an appointment with a GP or nurse the last time they tried, the calculations were so flawed that the CQC has been forced to remove the indicator altogether.

A further four indicators had to be refined based on revisions to data provided to the CQC by NHS England.

Hundreds of practices will now be assigned a different band.

In its initial register, published two weeks ago, the health watchdog ranked 7,276 practices out of the total 7,661 in England, and placed 864 practices in the "highest concern" category.

Original rankings

Image copyright Care Quality Commission

As a result of the recalculations, around 60 practices will be lifted out of the two "highest concern" categories, and four that were previously deemed low-risk have been found to be in need of early inspection.

The CQC says 519 practices will move bands, but most were between the lowest risk bands.

The CQC register was set up to help target inspections, and the watchdog said it did not necessarily indicate poor GP surgery performance.

Sir Mike Richards, chief inspector of hospitals for the CQC, told the BBC: "We will make them a big apology. This only became apparent when we ran the data on the thousands of practices rather than just the hundreds that we tested them on."

He defended the publication of the risk bands in the interest of transparency.

He said: "We are using the data to help us know where we might go first. Our judgement comes from a combination of data and inspection. The main thing that is going to matter is that we are going to be inspecting every practice."

Poor data

Measures removed

Whether patients were able to get an appointment with a doctor or nurse last time they tried

Measures recalculated

Coronary heart disease incidence

Chronic obstructive pulmonary disease (COPD) incidence

Unnecessary A&E admissions

Dementia diagnosis rates

The British Medical Association said mistakes by the CQC risked "doing serious harm" to the reputation of good surgeries.

Its GP committee chair, Dr Chaand Nagpaul, said: "The banding system as a whole needs to be withdrawn.

We warned at the time that simplistic targets would fail to take into account the enormous pressures GP practices are facing, and that skewed and limited information does not tell us about the quality of care.

"These failings have the potential to seriously undermine the trust in the system and patients' confidence in their GP and it is only right that all of those practices affected are now contacted and receive a full apology."