Vexia is banging out new "Econav" GPS devices with the launch of the Econav 480 and 380 in the UK in time for Christmas.

As with previous models, they launch with the boast of informing you of the most ecological and economical way to drive.

The 480 gets a 4.3-inch screen and the 380 a 3.5-inch screen and both offer advice on excessive acceleration and braking, when you are approaching or breaking the speed limit, when to change gear, and what a safe following distance is, so sound like an ideal replacement for a nagging back seat driver.

The new Econav models are slimmer and lighter than predecessors and include "Econav Reports", which document the fuel savings made by day, week or month.

The Econav 480 and 380 will be available during December from Amazon with pricing coming in at £210 for a Euro 480 and £180 for a UK version. The Econav 380 will cost £180 and £150.