Looking for a toilet in a hurry? First came SatNav for lost drivers, now there's SatLav, a toilet-finding service to help people caught short in central London.

The Westminster City Council launched a new SMS message service that will guide Londoners and tourists to their nearest public lavatory.

The toilet hunter can use this service by texting 'toilet' to 80097 and the location will be automatically sent to their phone. The 'SatLav' system charges 50 cents (25 pence) for each sms.

Student Gail Knight, 26, came up with the idea for an innovation competition run by the council.

When I'm out with friends, we're always ducking into McDonalds or department stores to use their loos. But we feel a bit bad about it, she said. I thought a text service would be really useful for people on the move.