The US Government has warned that the worldwide network of satellites that makes up the Global Positioning System could fail by next year, affecting millions of people around the globe.

Many depend on the satellite navigation network to beam precise directions from A to B into users' cars or on their mobile phones.

But mismanagement and a lack of investment means the 20-year-old system could lead consumers into nothing but trouble.

The first replacement satellite was supposed to be launched into space in 2007, but won't be ready until November - nearly three years too late.

And it is unclear whether the satellites in orbit will be able to keep the system running until their replacements arrive.

The satnav system could begin to fail as early as next year, according to a US Government Accountability Office study.

One in three motorists is already being sent the wrong way by satnav.

This failure could open the door to systems funded by other countries, such as Europe's Galileo network.

The EU-funded system, designed to rival the American network, is due to be launched next year - hopefully just in time for the fallout from the predicted failure of GPS.

The network of GPS satellites is overseen by the US Air Force, which was slammed in the accountability report for failing to keep the system up to date.

The air force is spending $1.7 billion to bring the system up to scratch, but the report claimed that constant delays and overspending had put the system in danger of failure.