Harry Beck's iconic map of the tube network has been honoured today with a Google Doodle .This is to mark the 150 anniversary of the Metropolitan Railway's first underground journey. The railway, opened to the public on 9 January 1863, passengers could travel between Paddington and Farringdon stations, which now forms part of the Circle and District Line.

As part of the celebration, London Underground will recreate this historic first journey on Sunday, with a restored steam locomotive and carriage. The Metropolitan Railway was linked six years later by the Metropolitan District Railway between Westminster and South Kensington, run by a rival company. The two were connected in 1884 by the Inner Circle. London's Metropolitan Railway became the world's first underground passenger line when it opened in January 1863. Built by a private company, the 3.5 mile (5.6km) line linked Paddington, Euston and King's Cross with the business district of central London. More than 2,000 workers built the line, mostly by hand. They dug a shallow cutting for the track before roofing it over to form a tunnel. The original gas-lit carriages were pulled by steam engines before electrification was introduced in the early 1900s. The noxious fumes from the engines left many passengers feeling ill and, despite ventilation efforts, prompted many complaints.