The urban transport app Citymapper has launched an on-demand minibus service in London, a cross between Uber and a traditional bus network that marks the latest attempt by a tech company to crash the capital’s transport market.

Starting from Wednesday, the company is running a fleet of eight-seater Mercedes Viano buses that will pick up and drop off passengers at fixed points on a road network, with a service called "smart rides".

Like Uber, the company plans to charge users for rides, and the vehicles will be on-demand, responding to orders placed by users on the Citymapper app, instead of travelling along fixed routes.

However, unlike the taxi app, they will only travel on pre-defined roads and passengers will be dropped off and picked up only at certain points, rather than wherever passengers demand. All journeys will be shared rather than catering to individuals.

Citymapper is launching the service with a free trial in a small area of central London that includes Euston, St Paul’s and Blackfriars but Omid Ashtari, the company’s president and head of business, said it plans to expand the service soon. It has a licence for up to 500 bus drivers, who will be self-employed and operate their own vehicles.