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
M25 motorway motorways. The M25 is the second-longest ring road in Europe, after the Berlin Ring (A 10), which is longer. Other cities in the UK encircled by motorways include: Birmingham, using parts of the M5, M6 and M42, and Manchester, using the M60. Additionally, from 2011 Glasgow has an orbital motorway made of the M8, M73 and M74, although one section of the route passes through the centre of the city. The M25 is one of the busiest motorways in Europe. Here are some comparisons: Iain Sinclair's 2002 book and film "London Orbital" is based on a year-long journey around the