A new concept phone on show today could spell the end to having to carry your house keys around with you.

The concept phone from DoCoMo called the Osaifu-Keitai works in connection with a special door lock to lock and unlock your front door.

The device will even go one step further and text you a message to let you know when certain people, i.e., your kids, have arrived home, as well as allowing you to check the status of your lock remotely via an i-mode website.

Finally, the company has also added sensory feedback to the handset to confirm when the operation has worked.

No word as yet as to when the system will be coming to the UK. Unfortunately i-mode failed to take off in the UK when it was originally launched with O2.

We will keep you posted.