From Kiosk No. 3 onwards, all the kiosk range had internal lighting. Originally this was achieved with a 25-watt bayonet bulb fitted in a brass, batten style, light fitting. This lamp fitting had a special ring that would only release the bulb with the use of a special tool.
Controlling the lamp was a time switch. These could vary in nature from a simple on/off type to the GPO Venner time switch. The correct position for these was under the board and to the left (see attached picture) The electrical intake would generally be to the right. In some areas the time switch has been located in other positions, one of them being at the top of the backboard!
By the 1960s most of the time switches were installed in a Case, Time Switch, No. 2, which would have a Time-switch No. 2 and Solar Dial No. 2 fitted within. The time switch was interesting as it had a solar dial that could be easily changed. The GPO used 9 different Solar Dials depending on the location of the kiosk. The Solar Dial switched the light off half an hour before sunrise and on hour an hour after sunset taking into account the month of the year.
The box containing the Venner time switch was lockable with a special key and on the right-hand side, on early boxes, there was a non-lockable toggle switch for testing the light.