M25

Proper noun

the M25

1. An orbital motorway surrounding Greater London, notorious for its general congestion.
   • DCI Tom Barnaby: And so the empty bottle in his hand?
     Dr George Bullard: Should've contained heart pills. Arteries like the M25.1998 May 6, Douglas Watkinson et al., “Death in Disguise”, in Midsomer Murders
2. (figuratively) The notional border between London and the rest of the UK.
   • Under the Communications Act 2003, all the commercial public service broadcasters are therefore required to commission certain levels of network programming from outside the M25 by value and volume.2007, Great Britain: Parliament: House of Commons: Culture, Media and Sport Committee, Public Service Content: First Report of Session 2007-08, Vol. 2: Oral and Written Evidence, The Stationery...
   • That's quite an achievement, I think, for someone inside the M25 to travel north, especially someone with such a plummy accent.2009, Maria Roberts, Single Mother on the Verge, Penguin UK, →ISBN