Citymapper, the popular public transport app, is launching a free bus service in London, a first step towards running its own transport services.

The app, which is currently used by commuters to find their quickest way around cities, will test the "smart bus" service this week.

The "CMX1" route, which will be tested on Tuesday May 9 and Wednesday May 10, will take passengers on a circle around the river Thames near Waterloo and Blackfriars. It will be free to ride and stop at existing bus stops.