Mobile phone seller Carphone Warehouse has launched what is likely to be the cheapest satnav system in the UK.

Myphone Satnav, priced at just £40, works on any Java-enabled mobile phone, although it needs Bluetooth too. The device has been sourced from German firm Jentro , where it's been on sale for a few months.

You don't get any maps included in the price; these have to be subscribed to for £5 per month, or £50 for a year's supply of maps. The maps have to be downloaded from Jentro's website.

Still it should be an attractive option for existing mobile phone owners who don't want to shell out at least three times the price for a complete satnav system, or other similar GPS for mobile phone options. For example, the TomTom Mobile 5 package costs around £200, five times as much as Carphone Warehouse's option.

Myphone Satnav comes with a standalone GPS receiver which communicates with the handset via Bluetooth. It is available now.