Bug busters at Dyson's Malmesbury factory are trying to beat the dust mites that cause allergic reaction but the breakthrough comes at a price as RONAN McCAUGHEY discovered.

"Nasty little buggers," was a German journalist's reaction to being told by a Dyson microbiologist that dust mites are the number one cause of allergies in the home.

The company's founder, the billionaire inventor James Dyson, gave a rare glimpse behind the doors of its hush-hush research and development department last week to demonstrate to reporters from around the world its on-going battle against the microscopic mites.

His state of the art factory on Tetbury Hill, Malmesbury has a futuristic feel with its curved roofline and silver opaque windows. This space-age feel continues inside where a biometric security system on the doors to research departments allows the staff to fingerprint in and keep the spies out.

Milling through were the young bug-busting engineers and scientists in jeans and casual shirts.

A mocked-up bedroom inside the plant was the scene for Dyson microbiologist Toby Saville to deliver a stream of allergy facts.

The T-shirt clad scientist said the bedroom provides the ideal conditions for the dust mite, because it thrives on warm and humid conditions, feeding on the skin cells left in pillows, duvets and mattresses.

With that pleasant thought he moved on to explaining how it is not the dust mite itself which generally triggers an allergic reaction but rather the 20 droppings a day it produces and its decomposing body parts.

Dust mites aka nasty little buggers feed on human and animal skin flakes. And over a week people can lose up to 28grams of skin, which is the weight of a bag of crisps, according to Mr Saville.

The firm boasts that the technology developed at Malmesbury means that Dyson vacuum cleaners pick up more dirt and allergens from the home, and make the air expelled from the machines 150 times cleaner to breathe.

But the firm's vacuum cleaners specifically designed for allergy sufferers don't come cheap. They range from £259.99 to £339.99, compared with the £189.99 for the basic model Dyson.

For those who cannot afford the machines, Mr Saville recommended practical allergy busting solutions like vacuuming mattresses, pillow covers and sheets to kill the dust mites.

Teenagers too lazy to make their beds in the morning were also praised by the scientist.

He said making a bed only gives he dust mites more heat and time to feed.

Mr Saville said soft toys were another dust-gatherer and recommended giving them a hot wash or putting the in the freezer to exterminate the mites.

The factory hummed with activity, acting as a reminder that this is the centre of Dyson's research and development operation.

Inside one lab I caught a glimpse of two men running a vacuum cleaner down a table. Perhaps it was a new design but it was obviously a secret because the public relations team shepherded me to join the rest of the media team.

Some 15 years ago, James Dyson launched the Dyson DC01 Dual Cyclone vacuum cleaner.

It took 5,000 prototypes and numerous rejection letters to get there.

But today Mr Dyson employs 1,200 people including 350 engineers and scientists at the Malmesbury plant.

His company's products are the biggest sellers in Britain, America, Europe and Australia.

Over lunch the stylishly-dressed entrepreneur admitted he should spend more time with housewives to get feedback on his cleaners.

The inventor, who himself studied design and engineering, said much of his time was spent working alongside other engineers developing new machines.

He said: "I am very proud to have the plant in Malmesbury. We put a lot of money into the local economy and I hope people are happy with it."

The questions over, Mr Dyson left to catch a flight to the U.S where he was launching the new DC15 Ball cleaner.

Dyson spokeswoman Laura Brock said the war on allergens continues. Last year the firm invested £40million in R&D and plans to invest £10million more next year.

She said: "These days more and more people are concerned about allergies such as hay fever and eczema. And the fact that we rely on central heating in the UK means the conditions are ripe for dust mites and bacteria, which can trigger allergic reactions. We are also the only appliance company in Europe to have a microbiology lab. This shows our commitment to preventing allergies."