THE stinger is an extremely clever device, simple yet effective. Its makers claim it is probably the safest way to stop a speeding car.

This week there was an intense political row over the stinger after conflict between the Garda and the Minister for Justice, Mrs Owen, over a new-law on the use of the device.

The background to the row was a tragedy - two teenage boys died in Cork after being struck on Monday night by a stolen car being driven at speed. Shortly afterwards, the Garda said they would have been unable to use the stinger against any alleged car thieves because the law allowed for its use only against people engaged in serious crime, such as escaping bank robbers.

On Wednesday night the Minister, Mrs Owen, told the Dail her Department had informed the Garda a week before the Cork incident that the law had been changed and they could use the device against car thieves. It was for the Garda authorities to tell members about the new law.

The irony about the apparent delay in gardai using the new law is that it was the Garda itself which had pressed for the device to be deployed against car thieves.

The force has 152 stingers, costing £500 each, and training in their use has been taking place. The stinger is a plastic and metal device which can be thrown in front of a speeding car. It comes folded in a briefcase but can be quickly extended across a road. The company in the UK which manufactures the device makes two versions, one 15 feet and the other 25 feet. The Garda has bought the 15-foot version.

The problem of stopping speeding cars safely is a worldwide one. One invention tested in Finland involved a long metal pole attached to the front of a high- powered pursuit car. This pole is rammed into the rear of the car being pursued and the target car can then be brought to a halt. This is not regarded as the sophisticated end of the market.

In the US, police forces are examining another method whereby the chase car fires an electronic charge at the car in front cutting out its electrical circuits. However, there are dangers if the pursued driver suddenly loses control.

The stinger works because by all accounts, including Garda tests it stops the speeding car without sending it out of control. The device has hollow metal spikes, designed to enter all four tyres when a car drives over them. There are small plastic arms on the spikes so that the tyre rocks the device slightly forward as it passes across, allowing the spikes to enter the rubber at right-angles. The hollow spikes stay in the tyres and air escapes through them.

Devices such as the stinger are designed to be used by police officers following a co-ordinated strategy against a speeding car. Officers are expected to force the car into a narrow stretch of road where the stinger cannot be avoided. The officer who throws the stinger on the road quickly pulls it back once the target car has been "spiked" so that pursuing police cars can pass.

The tyres on the "spiked" car deflate in moments at a steady rate. Tests show that the car will usually come to a halt in a straight line after a few hundred yards.

It is wrong to suggest that had they known of the change in the law, gardai in Cork could have saved the lives of two teenagers by deploying a stinger. There were no gardai nearby when the incident occurred. But it is right to ask whether the Department of Justice and the force acted quickly enough when the new law was brought into effect.

The Garda has been examining stingers for some time and it was known last month that the provision allowing their use against car thieves was about to be enacted. If the practice which "has become quite improperly, in my view, to be known as joyriding" (in the words of the Minister) was one of grave concern to the authorities, then one might have expected gardai to be trained and equipped to use the device against car thieves from March 4th, the day the President signed the relevant provision into law.

Police officers gather information from a number of sources. They read articles such as the one in the current issue of Garda Review, the official magazine for officers of garda rank.

A COMPREHENSIVE article in the March issue explains how to use the stinger, but also notes: "It is not being used to catch `joyriders' but this may come under review if legislation in this area is changed." This suggests a legal change was some way oft, rather than already complete.

The response from senior Garda sources is that any new law has to be methodically examined before it is put into effect. Legislation must be distilled into clear operational guidelines for gardai who will implement it.

On Wednesday night the Minister in effect shunted the blame for any delay in deploying the stinger to the Garda. She said she wash not trying to blame anyone but her purpose in asserting that Garda management knew of the legal change a week before the Cork incident was apparent.

Her political opponents were quick to point out that while the Garda may be responsible for Garda matters, it is up to the Minister to ensure that new law is implemented. It is the Minister who must explain to the public and to TDs whether a law which has been passed is working or not.

The new stinger law might have been a good opportunity for the Minister to demonstrate the Government's much-trumpeted emphasis on crime by announcing to the public at large, and criminals in particular, that speeding car thieves were now far more likely to be caught. On the contrary, the legal change was so low-key that not even gardai knew about it.

It is worth remembering that the public said in a referendum last November that it wanted to tighten the bail laws by allowing for preventive detention. The law to give effect to that decision has not yet emerged, some 3 1/2 months later. The Minister has worked hard to make significant changes during her term in office but somehow episodes like the stinger affair keep cropping up to give an impression of inertia.

Meanwhile, the Garda says officers in all its divisions will be trained in the use of the stinger within three weeks, five weeks after the new law came into force.