Scientists have discovered a groundbreaking drug that could "signal the end to allergies", transform the lives of millions of sufferers and save hundreds of lives a year.

Researchers have discovered a protein that blocks the pathways that cause allergic symptoms such as wheezing, runny nose, rashes and potentially lethal allergic shock.

They believe the new drug, which has almost no side effects, could completely eliminate allergy symptoms - from hay fever to potentially lethal nut allergies - that blight the lives of up to a third of all Britons.

It could save the National Health Service up to £1billion a year and it could be on the market within six years.

Ido Bachelet, a key scientist in the award-winning project at the University of Jerusalem, said he believed the product could ultimately "signal the end" to many allergies altogether.

He said: "We have shown this to be very effective. From what we have seen this can eliminate allergies regardless of their location in the body. I am very excited by this and we are trying to advance it as quickly as possible."

Dr Peter Howarth, leading allergy expert at Southampton University, also welcomed the discovery. He said: "This advance opens hope for allergy sufferers for the future. It is extremely promising and we await with anticipation development in terms of human trials."

He added: "We need new and better drugs as existing therapies are not effective in all patients. This one should be very safe."

Professor Jonathan Brostoff, an allergy specialist at Kings College, London, agreed the findings, "sounded fantastic", though he also added more research was necessary.

The astonishing news comes as the NHS reveals it now spends £1billion a year struggling to cope with a growing allergy epidemic, with 18 million people now developing some sort of allergy during their lifetime. For many years scientists have been frustrated with existing anti-allergy therapies, including steroids and antihistamines, which only relieve symptoms and can have serious side effects.

The team focussed their work on mast cells - the part of the immune system that helps the body overcome bacteria and parasites.

These cells are found in body tissues including the eye, nose, airways, skin and gut. In allergy sufferers the cells inexplicably react to inert substances such as certain foods, dust mites and pollen.

But the University of Jerusalem researchers discovered a naturally occurring protein that "instructs" mast cells not to react in this way. They have successfully used it in laboratory experiments and plan to test it on humans within the next year.

Allergy sufferers were excited by the news. Simone Sagi, 34, a support worker for the group Allergy UK, who suffers severe food allergies, said that living with her allergy "can be a nightmare".

Ms Sagi, an exhibitions organiser from north London, was diagnosed with food allergies in her mid-20s when she lost more than three stone "in a short space of time".

She said: "I was a healthy nine-and-a-half stone and by the time doctors found out what was wrong I was six-and-a-half stone.

"I was being sick constantly, I felt weak, tired, depressed and very worried, but no one could work out what was happening."

Eventually doctors discovered she was allergic to a large range of foods including fish, nuts, wheat, many fruits, chocolate and coffee.

"I now have to take my own food to restaurants or when I go out, and many people treat you really badly when you do this.

"If I could take a drug that would get rid of the allergy it would be the most fantastic thing that could happen to me. It blights my life, though I know there are many allergy sufferers far worse off than I am."

Allergy rates have soared in the last 20 years. Rates of asthma have doubled, with the condition affecting five million people in England alone. Figures for hay fever have also soared, with one in four Britons suffering an allergy to pollen.

There has also been a sharp rise in anaphylaxis, the most severe form of allergic reaction, with more than 3,000 Britons taken to hospital and up to 20 dying last year.