London and Home Counties

Areas covered: The zone bounded by a line commencing at Tring, proceeding in a Southerly direction to Chesham, Amersham, Beaconsfield, Eton, Winsor, Farnborough to Farnam in an Easterly direction to Godalming, Dorking, Reigate, Redhill, Westerham in a North-Easterly direction to Dartford then in an Easterly direction to Tilbury, along the Thames Estuary and the coast to Maldon, in a Westerly direction to Chelmsford, Harlow, Hertford, Hatfield, St.Albans to Tring.