Central, West & North London
Westminster, City of London, Camden, Islington, Kensington & Chelsea, Hammersmith, Ealing, Brent, Wembley, Harrow, Barnet, Enfield, and Finchley (EC, WC, W, NW & N postcodes).
East, Docklands & South London
Canary Wharf, Tower Hamlets, Hackney, Stratford, Newham, Ilford, Romford, Barking, Southwark, Lambeth, Wandsworth, Greenwich, Lewisham, Bromley, and Croydon (E, IG, RM, SE & SW postcodes).
Outer London & West/South M25
Uxbridge, Hayes, Hounslow, Twickenham, Kingston upon Thames, Surbiton, Sutton, Epsom, Staines, Slough, Windsor, Reading, Woking, and Guildford (UB, TW, KT, SM, SL & GU postcodes).
Outer London & North/East M25
Watford, St Albans, Hemel Hempstead, Borehamwood, Loughton, Epping, Brentwood, Chelmsford, Dartford, Gravesend, Sevenoaks, and Maidstone (WD, AL, EN, CM, DA & TN postcodes).