MOBILE phone users may be putting themselves at higher risk of cancer, a major new study has confirmed.

The World Health Organisation-funded study has found that microwave radiation from mobile phones can increase the risk of brain tumours.

The agency has now listed mobile phones as a “carcinogenic hazard”, alongside lead, engine exhaust fumes and chloroform.

Before its announcement this week, the WHO had assured people that no ill-effects had been established.

A team of 31 scientists from 14 countries made the decision after reviewing peer-reviewed studies on mobile phone safety.

The team found evidence that personal exposure was “possibly carcinogenic to humans”.

This means that there is not enough long-term evidence to conclude if radiation from mobile phones is safe, but there is enough data to show a possible connection to tumours.

Mobile phones emit a kind of radiation known as non-ionising. It has been compared to a very low-powered microwave oven.

In the past 20 years the British public has shown a massive appetite for mobile telephony, with an estimated 76 million in use among a population of 62 million.

Cooking the brain: Dr Keith Black, chairman of neurology at Cedars-Sinai Medical Centre in Los Angeles, told CNN: “The biggest problem we have is that we know most environmental factors take several decades of exposure before we really see the consequences.

“What microwave radiation does in most simplistic terms is similar to what happens to food in microwaves, essentially cooking the brain.

“So in addition to leading to a development of cancer and tumours, there could be a whole host of other effects like cognitive memory function, since the memory temporal lobes are where we hold our cellphones.”

Young minds: The possible ill-effects of mobile phone radiation could be multiplied in youngsters, who have thinner skulls and scalps.

Even more grave are the possible effects on children, who have thinner skulls and scalps — allowing radiation to penetrate much more deeply into the brain.

The rapid cell division of young brains could also multiply the mutating effects of radiation, according to Dr Black.

The WHO’s warning joins a chorus of voices urging caution over excessive mobile phone use in recent years.

The European Environmental Agency has pushed for more studies, amid fears that the radiation from mobile phone handsets could be as dangerous to public health as smoking, asbestos and leaded petrol.

In 2010 the widest yet international study of the relationship between mobile phones and cancer found those who had used mobiles for a decade or more had double the rate of brain glioma, a type of tumour.

* Keep your mobile phone in your bag rather than in your pocket or next to your body. One study shows that men who wear cellphones near their groin risk reductions in their sperm count by up to 30 per cent.

* Send text messages or email where possible — don’t lean it against your body as you do so.

* Use a wireless headset. Moving your phone 20cm away from your head reduces radiation doses by about 98 per cent.

* Keep still when you’re using it. If you’re on the move, whether walking or in a vehicle, your phone needs to use more radiation to keep track of you.

* Hold it away from you after dialling and watch the screen to see when it connects. Most phones emit more radiation when they’re trying to make contact.

* Go low-tech. The more sophisticated functions your phone has, the more power it must use to complete tasks.

* Talk for hours on end. The longer you use the phone, the higher a dose of radiation your brain is soaking up. Even a two-minute call has been found to alter the natural electrical activity of the brain for up to an hour afterwards.

* Use a regular wired headset, like the one that came with your phone. The regular wired headset has been found to intensify radiation into the ear canal.

* Allow your children unlimited mobile phone use. Young brains encased in thinner, more fragile skulls risk greater damage.

* Do not make a call when the signal strength is one bar or less. The phone must work harder to establish a connection.

* Use the cellphone in enclosed metal spaces such as vehicles or elevators, where devices may use more power to establish connection. The metal enclosure also acts as a Faraday cage that traps the radiation and reflects it back on to the occupants.

How mobile phone radiation could be the next big public health crisis.

The safety risks of mobile phones is a matter of constant contention between scientists and grave concern for consumers.

Just a fortnight ago an influential Council of Europe committee warned mobile phones and wireless internet should be banned from schools because they pose too great a risk to children’s health.

The Council’s Committee on the Environment, Agriculture and Local and Regional Affairs drew up a draft resolution urging governments to ‘take all reasonable measures to reduce exposure to electromagnetic fields’ from mobile phones and similar devices.

Danger: the Council of Europe believes that mobile phones should be banned from schools as they affect the developing brain.

In March, in the Government’s first update to the UK Mobile Phones and Health leaflet since 2005, officials for the first time warned mobile phone users to text or use hands-free kits rather than make calls.

The Department of Health said this would reduce the user’s exposure to reduce radiation emitted by the devices.

It stated there had been no “clear evidence of adverse health effects” from the use of mobiles or from phone masts.

However, it added: “As people have only been using mobile phones for relatively few years, the HPA advises that more research be carried out, especially to investigate whether there might be longer term effects.”

Mobile phone users are now encouraged to use hands-free kits or text rather than holding phones to their heads.

The UK Chief Medical Officer restated previous advice that children under the age of 16 should only use mobile phones for “essential purposes” and should “keep calls short”.

This was described as a ‘precautionary’ move as teenagers’ bodies and nervous systems are still developing.

Children under 16 should limit use to essential calls.

But a month earlier a University of Manchester study found there was no link between mobile phone use and increased levels of brain cancer.

A study by scientists at the university looked at data from the Office of National Statistics on rates of newly diagnosed brain cancers in England between 1998 and 2007.

It found no statistically significant change in the incidence of brain cancers in men or women during the nine-year period.

Lead researcher Dr Frank de Vocht, an expert in occupational and environmental health in the University of Manchester’s School of Community-Based Medicine, said a cancer epidemic was unlikely.

He said: “Our findings indicate that a causal link between mobile phone use and cancer is unlikely because there is no evidence of any significant increase in the disease since their introduction and rapid proliferation.”

But at the end of 2010 a startling survey warned pregnant women who regularly use mobile phones could increase the risk of their children behaving badly.

If their offspring then start using the devices at an early age, the chance of problems climbs to 50 per cent, according to findings published in the Journal of Epidemiology and Community Health.

Researchers in California found those exposed to mobile phones in the womb had a 30 per cent rise in behavioural difficulties at the age of seven.

But those exposed before birth and in their childhood, were 50 per cent more likely to have behavioural problems than those exposed to neither.

Researchers suggest that pregnant women who regularly use mobile phones are putting their babies at risk of developing behavioural problems.

Children who used mobiles, but were not exposed in the womb, were 20 per cent more likely to display abnormal behaviour.

These latest studies have just contributed to a contradictory canon of research into mobile phone safety.

As far back as 2000, a Government-funded report found that while there was no concrete proof that mobile phones were harmful to health, use of the devices should be limited.

Most scientists say it is still too early to tell whether mobile phones are safe in the long term, and the Government’s Mobile Telecommunications and Health Research Programme is still calling for further research.