GPs prescribe antibiotics to 97% of patients on request - despite increasing resistance to the drugs, new research suggests.

According to the study, more than half of those who visit the doctor with a cough or cold still expect to be given the medication, regardless of the fact that most viruses do not respond to the treatment.

The findings come amid growing fears that overuse of antibiotics could render the drugs redundant and unable to tackle serious infections like hospital bugs. Currently around 25,000 patients die each year in the EU from infections caused by bacteria which have grown resistant to antimicrobial medicines, including antibiotics.

The research, commissioned by the Health Protection Agency (HPA), showed 97% of patients said their GP or nurse put them on a course of antibiotics the last time they asked for a prescription.

Some 20% of adults consulted for the study said they made an appointment to see their doctor for a recent respiratory tract infection, such as a sore throat or flu. Of these, 53% expected to be prescribed antibiotics and 25% said they believed antibiotics worked on most coughs and colds.

The study also found that one in 10 people admitted to keeping leftover antibiotics - a habit which can exacerbate the developing resistance to the drug if individuals decide to treat themselves at a later stage.

Dr Cliodna McNulty, the HPA's head of primary care, said: "Although the public recognises resistance as a problem, our findings show that people expect, and are often prescribed, antibiotics for mild illnesses such as coughs, colds and sore throats as well as for flu, which can be more severe, but is still a viral illness. Health professionals need to learn to resist demands from patients for treatments they know have little or no effect on coughs and colds."

Professor Laura Piddock, from the University of Birmingham's School of Immunity and Infection, called for action to counter the "spectre of untreatable infections".

Writing in medical journal The Lancet, she said some people's lives depend on antibiotics. "Very sophisticated technology-dependent medical procedures are often used for elderly patients," she said. "Because of the infections associated with such procedures, antibiotics are an integral and routine part of treatment. Antibiotics are also an important addition to treatment of many patients with cancer, improving survival rates.

"When these patients are denied treatment with a new cancer drug because of its expense, there is public outrage despite the possibility of extending life by only a few weeks. Antibiotics are not perceived as essential to health or the practice of medicine, despite such agents saving lives so that individuals can live for many years after infection."