A new device that promises an end to "nuisance" phone calls has launched in the UK, with backing from television's The Dragon's Den.

"trueCall" plugs into your home phone line and, dependent on settings, blocks calls from numbers that have not been registered with the device, giving the user the option to take the call or not.

trueCall checks every call received before even letting your phone ring. It will connect callers whose numbers are on the "Star List" straight away but telemarketing, market research, recorded messages and the like will be stopped.

This works if trueCall does not recognise the caller’s number or the number has been withheld, as it will "ask" the caller who they are and where they are calling from before putting them on hold and passing this info onto the user.

The user can then accept the call, get trueCall to take a message or put them on a Zap black-list, which means if they call again, trueCall will inform them the call is not of interest.

Said to be about the size of a paperback book, right now the device is available from John Lewis for £97.50, over at eXpansys for £79.97, via the BT Online shop or direct at www.trucall.co.uk.