The London Underground is patrolled by the British Transport Police (BTP). Over 12,000 CCTV cameras are used to monitor the London Underground stations, depots, car parks and trains. TimelineJanuary 9, 1863 – The London Underground begins running on the Metropolitan Railway. 1869 – East London Line opens (orange line on the map). Three small devices explode at three separate Underground subway stations, two weeks after the July 7 terror attacks.