Groundbreaking research has analyzed 11 million courses of antibiotics prescribed to British patients over the last 22 years covering the most common diseases areas including tonsillitis, pneumonia and ear infections.

Scientists said the findings were 'bleak' with one in six courses of antibiotics failing in 2012 but for some drugs this was more than one in two.

Experts and governments have warned that antibiotic resistance is one of the greatest threats to modern health care yet prescriptions of the drugs by family doctors continues to increase.

Providers have admitted prescribing antibiotics to 'get rid of' patients.

This comes after it was revealed that Providers in some areas of the country are prescribing twice as many antibiotics as in others, with rates lowest in London and highest in the north of the country.

Cardiff University researchers found that as GP prescriptions of antibiotics rose in recent years so did the proportion of the treatment courses that ended in failure.

This was defined as when patients needed another course of drugs within a month, were admitted to hospital with an infection within 30 days, had other complicating factors relating to infection or died from conditions relating to the infection.

They looked at common antibiotics prescribed for upper respiratory tract infections such as sinusitis and tonsillitis; lower respiratory tract infections, such as bronchitis and pneumonia; skin and soft tissue infections, and middle-ear infection.

Between 1991 and 2012 overall antibiotic failures increased from 13.9 per cent to 15.4 per cent.

Failure rates for lower respiratory tract infections such as bronchitis and pneumonia were worse with more than one in three courses resulting in further complications or treatment.

One drug, trimethoprim, an antibiotic normally used in the treatment of upper respiratory tract infections such as tonsillitis and listed on the World Health Organizations's register of ‘essential medicines’, failed up to 70 per cent of the time when used to treat bronchitis or pneumonia. This compared with the more commonly prescribed amoxicillin which failed 18 per cent of the time for those diseases.

The researchers, writing in the British Medical Journal, warned that the failure rates might even be an underestimate because if antibiotics were prescribed spuriously for viral diseases and no follow-up treatment required then it would not have registered as a 'failure'.

Professor Craig Currie from Cardiff University’s School of Medicine, said: “There is a strong link between the rise in antibiotic treatment failure and an increase in prescriptions.

“Between 2000 and 2012, the proportion of infections being treated with antibiotics rose from 60 per cent to 65 per cent which is the period in which we see the biggest increase in antibiotic failure rates. These episodes of failure were most striking when the antibiotic selected was not considered first choice for the condition treated.

“Given the lack of new antibiotics being developed, the growing ineffectiveness of antibiotics delivered through primary care is very worrying indeed.

"There is a mistaken perception that antibiotic resistance is only a danger admitted to hospital patients, but recent antibiotic use in primary care is the single most important risk factor for an infection with a resistant organism. "Furthermore, what happens in primary care impacts on hospital care and vice versa.

“Antibiotic resistance in primary care needs to be more closely monitored, which is actually quite difficult given that primary care clinicians seldom report treatment failures. The association between antibiotic resistance and antibiotic treatment failure also needs to be further explored. From the general level of feverish debate, it’s not quite the "cliff" we would have imagined, but clearly this is worrying.”

David Cameron has set up an antibiotic resistance task force and has warned the issue threatens to send medicine 'back to the Dark Ages'.

Increasing numbers of infections are now resistant to all common antibiotics making them almost impossible to treat and few new drugs are in the pipeline.

Professor Currie added: “We need to ensure that patients receive the appropriate medication for their condition and minimize any unnecessary or inappropriate treatment which could be fueling microbial resistance to antibiotics, prolonging illness and in some cases killing people.”

The research was only possible because the team had access to anonymous medical records of more than 14 million people from more than 700 Family Practices in the UK.

Dr Richard Stabler, Senior Lecturer in Molecular Bacteriology at the London School of Hygiene & Tropical Medicine, said: “The overall picture presented is bleak but not unexpected, with rises in drug resistance rising in most categories.

"The increase in resistance is possibly lower than expected, certainly in comparison to hospital based studies, but without action and a continual increase in resistance, antimicrobial resistance is still a real threat.

“Treatable infections becoming untreatable is a real possibility with several important infections, for example Tuberculosis and gonorrhea, having already been documented to be almost totally resistant to all known classes of antimicrobials in some cases.”