'Don't trust DIY breath tests'

Motorists are warned today to avoid DIY breathalysers after tests showed they could give wildly inaccurate results.

Researchers found that four in 10 of the most popular self-testing devices, ranging in price from £2 to £129, gave inaccurate readings.

Experts claim that even the accurate machines could lose their ability to read a driver's breath alcohol concentration correctly.

The findings are a blow for motorists who use the devices in the belief that they can drink up to the legal limit and then drive safely, but they prove what drink-drive experts have feared for years. A spokesman for Intoximeters UK, the organisation that supplies the £6,000 desktop machines used to collect evidence at police stations, and which helped with the investigation, said: "Calibration on machines like these is sensitive and can be misleading.

"If people do want to use selfbreathalysers, they must be aware that they are simply a rough indication of how much you've had to drink. You shouldn't risk your life or your

licence on their readouts."

The trials, published today by Auto Express magazine, included both " blow-in-the-bag" testers and more sophisticated battery-powered devices available from shops, some pubs, motorway service stations and the internet.

A spokesman for the Association of Chief Police Officers backed the results of the tests.

He said: "We don't support the use of these because there are question marks over their accuracy, particularly as over time the calibration of the machines may deteriorate.

"There is a danger that drivers will test themselves, the machine will show they are under the limit and they will either be tempted to continue drinking, or drive while the alcohol limit in their blood stream is still rising, with potentially dangerous consequences."

Of the 10 machines tested by Auto Express and Intoximeters, the Breathscan (£2), the Comtech AML 201 (£34.95), the SAFE (£29.99) and the Matsutek Trooper 2000 (£70) all gave inaccurate readings.

The devices that read accurately were the Original Breathalyzer (£3.99), the Redline (£10), the ABI Scientific (£94), the ACE tec (£129), the Tanita Alcohol Sensor (£24.95) and the BT3500 (£62).

Apart from the first two, which are "blow in the bag", the four others are electronic machines.

The results follow the latest figures from the Department for Transport, showing the number of drivers killed while over the legal alcohol limit increased by 13per cent between 1999 and 2000.

It is now at its highest level since 1990.