London Mayor Sadiq Khan says an all-night underground service will start running on two of the city's lines in August.

He said Monday the initial all-night service will be offered on weekends on the Central and Victoria lines from Aug. 19.

The service will be added on the Jubilee, Northern and Piccadilly lines in the fall as more drivers are trained.

Khan said the expanded service "is absolutely vital to my plans to support and grow London's night-time economy."

He said the all-night service will help spur job creation.