It is perhaps the secret fear of all users of GPS systems: what if the device gets it wrong and leads you into danger?

The Spanish Red Cross said today this was exactly what happened to a 37-year-old man who died on Saturday night after driving his car into a reservoir near the western town of Capilla.

"It seems the GPS system pointed them on to an old road that ends in the reservoir, and that in the dark they were unable to brake in time, with the car taking just a couple of minutes to sink," the Red Cross said in a statement.

The victim and a single passenger were driving home towards the southern city of Seville after working at a street fair when the Peugeot 306 ploughed straight into the waters of La Serena reservoir.

Although both men managed to get out of the car, only one made it to the shore. Red Cross divers found the body of the unnamed driver at the bottom of the reservoir on Sunday morning.

The passenger was treated for bruising and light injuries.

Pictures of the scene show the old road running on a slight downhill slope straight into the reservoir, which is the biggest in the country.

There was no explanation of why the GPS still showed the road as usable. La Serena reservoir, which stores water from the Zújar river, was built in 1989.