M25 motorway and Thurrock off junction 31 (to the east of London). Cobham services opened on 13 September 2012. Originally, the M25 was unlit except for sections around Heathrow, major interchanges and Junctions 23–30. Originally, low pressure sodium (SOX) lighting was the most prominent technology used, but widening projects from the 1990s onwards have all used high-pressure sodium (SON) lighting and this has diminished the original installations. By 2014 only one significant stretch was still SOX-lit (Junction 25–26) and the units were removed the same year. The motorway passes through five counties. Junctions 1A–5 are in Kent, 6–14 are in Surrey, 15–16
Timeline of the London Underground of the network. Station names shown are current names; many stations have previously had different names. Timeline of the London Underground The transport system now known as the London Underground began in 1863 with the Metropolitan Railway, the world's first underground railway. Over the next forty years, the early sub-surface lines reached out from the urban centre of the capital into the surrounding rural margins, leading to the development of new commuter suburbs. At the turn of the nineteenth century, new technology—including electric locomotives and improvements to the tunnelling shield—enabled new companies to construct a series of "tube" lines deeper