The 1970's to 1980's
By the early 1970's much of the town centre lighting on many major routes was replaced by various GEC 'Turtles' (left) running what I assume were SON E lamps with routes away from the centre laterns running SOX either of 135w mostly GEC Z9554M (centre) or 9Ow Thorn Alpha 9 (right) varieties as seen below became prevelant.
The minor roads started to get either sox (usually 35W GEC Z9484 'boats') on concrete & Steel columns (left) or more commonly MBF GEC 8496 & 8896 (such as the conversion shown middle) or Thorn Beta 7 lanterns installed (right), some on new steel colums.
In the late 1980's and Early 1990's, wholesale replacement of lanterns on the town centre main roads took place though many of the steel columns were re-used, with the majority of the old GEC 'Turtles' being replaced with WRTL? MRL-6 lanterns running 150 or 250W SON (left) and on many roads away from the centre the many of the old GEC/Thorn SON's were replaced with various versions of Philips MA50, 60 & 90 running 90, 135 and some 180W SOX (right 135w MA eith internal gear)
On the minor roads there was some schemes of wholesale replacement with new columns containing post-top SON lanterns such as the two examples (the left one being extremly poor for light polution) below and in other areas some casual installation of SOX lighting, mainly Thorn Beta 5's on exisiting columns or hocky stick columns took place.
During the 2000's casual replacement continues with some streets having some complete replacement programmes. On main roads some casual replacement of SOX lighting has taken place, the lanterns installed in the early 2000's were often Philips SGS 203 and also some use of Philips Trafficvisions, Later in the decade new lanterns were normally either Philips Iridium (left) or Industria Arc (right) but always running SON lamps. Quite often the columns would not be changed though
In the minor roads some areas had complete replacement programmes, some Thorn Beta 5 running SON but more recently they tend to be Philips MI 26 (SGS 103) running 35W SOX (left) or WRTL 2600 running SON (middle), either on new hockey stick columns or re-using exisiting columns. the same applies with casual replacements in the town that still take place as required. There have also been use of Philips Streetfighter lanterns on posttop mounting or side mounting on hockeystick columns (right) in some alleyways. Some of the post top lanterns installed in the 1990's have been replaced with side entry lanterns on replacement brackets (centre).
During 2009/10 the WRTL ARC and Philips SGS 2003 became the norm for casual replacements and even some LED Stela's were tried (see replacement schemes) but in 2011 the WRTL Libra became the lantern of choice for casual replacements on side roads and the ARC remained the choice for major roads except for highways agency schemes where Philips Iridiums were used.
SInce 2010 large numbers of Indo Induction Lights and LED lights have started to be used. Please See replacement scheme pages for examples.