Important safety informationBatteries produce flammable gases, so:never try to jump start a battery that looks damaged or is leakingdon’t use jump leads that are damagedstop using the jump leads if they get hot. Switch off both engines and allow the leads to cool to avoid a possible firenever smoke or allow naked flames anywhere near either batterydon’t let any metal objects come in contact with the cars’ batteries, as these could cause a spark and possibly make the battery explode. That includes rings, necklaces, watch straps, hand tools, clips, stray wires etcDon't remove the jump leads while the cars’ engines are running. This can cause serious damage to the cars’ electronicsBefore you start, remove any loose-fitting clothing – like a scarf or tie – as these could get caught up in the moving engine partsA step-by-step guide (courtesy of the AA)Find someone with a car who’s happy to help. Their car must have a fully charged battery with the same voltage as yours (usually 12 volts)Park both cars so their batteries are within easy reach of one another (without the cars actually touching). Keep the handbrakes on and the ignitions offUse the red jump lead to connect the working battery’s positive (+) terminal to the flat battery’s positive (+) terminalTake the black jump lead and attach it to the negative (-) terminal on the working battery. Then attach the other end to an earthing point (unpainted metal on the engine block or chassis) well away from the flat battery and fuel systemKeep both engines off and wait for three minutes, then start the working car’s engine and let it run for a minuteStart your carLeave both cars to idle, at a fast pace, for around 10 minutesTurn off both cars’ engines and carefully disconnect the leads in the reverse order to the way they were connected (i.e. remove the black lead from your car first and finish with the red lead from the other car). Make sure the leads don’t touch one another, or either car, as you remove themRestart your carIf your car won’t start there’s probably a more serious problem requiring professional help