The initiative, which enables users to text "HOME" to Transport for London's short code 60835, is part of the "Know what you're getting into" campaign, which warns women of the dangers of using illegal minicabs and offers safer travel information.
Ken Livingstone, Mayor of London, said: "On average there are 10 sexual assaults or rapes carried out by illegal minicabs each month. Yet people are still using them. The new service means that people can now text "HOME" to 60835 and receive the numbers of licensed minicab and black cab firms in the area they are texting from."
The Greater London Authority's marketing team developed a marketing campaign for the service which includes poster advertising, radio and cinema ads and a promotion with radio station Heart 106.2.
The service uses mobile services company Incentivated's technology.
Jonathan Bass, managing director of Incentivated, said: "In terms of the mobile medium this is a great example of a simple idea that is accessible to most people, wherever they are, and is coupled with a good call to action and powerful technology."
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