A clampdown on antibiotics spewing into the River Thames through sewage pipes is needed to halt a surge of ultra-resistant superbugs, warns a new study.

Experts urged the authorities to act to cut the flow of antibiotics spilling into the river by up to 80 per cent to stop superbugs flourishing.

Three-quarters of the River Thames catchment harboured enough medicines for antibiotic-resistant bacteria to develop, according to scientists from the UK's Centre of Excellence for water research.

England's chief medical officer Professor Dame Sally Davies said last week that superbugs could wipe out humans before climate change, with the potential to kill at least 10 million people a year globally.

Up to 90 per cent of prescribed antibiotics taken by people pass through the body and into the sewerage system, where about half end up in rivers.

Lead researcher Dr Andrew Singer, of the Centre for Ecology and Hydrology, said: "Rivers are a 'reservoir' for antibiotic-resistant bacteria which can quickly spread to people via water, soil, air, food and animals.

"The release of drugs and bugs into our rivers increases the likelihood of antibiotic-resistant genes being shared, either through mutation or 'bacterial sex'.

"This is the first step towards the development of superbugs as the drugs used to fight them will no longer work."

The current research, The published in the journal PLOS One, was based on prescription data from clinical commissioning groups for two classes of antibiotics - macrolides and fluoroquinolones.

Macrolides - such as erythromycin and azithromycin - treat a range of respiratory and sexually transmitted infections including pneumonia, whooping cough and chlamydia.

Fluoroquinolones - including ciprofloxacin and levofloxacin - treat respiratory and urinary tract infections.

The researchers chose to study these antibiotics because they biodegrade slowly, unlike others which biodegrade before reaching the river.

Health experts have suggested several ways to reduce the amount of antibiotics entering rivers.

A widely accepted goal is to reduce unnecessarily long treatment courses and inappropriate prescriptions.

Another is to prevent the need for medicine by rapidly diagnosing medical conditions, increasing vaccinations and improving hospital hygiene.

Researchers also recommended investing more in developing better wastewater treatment technology capable of removing the drugs and bugs from sewage, a suggestion Thames Water backs.

Antibiotics consumed in primary and secondary care in England between 2014 and 2018 fell by more than six per cent, but UK prescriptions per person are still higher than in several European countries.

In the Netherlands, where there prescriptions are half the UK's, controls on prescribing antibiotics and good hospital hygiene have resulted in low rates of antibiotic resistance.