This is a genuine Lucas manufactured ignition switch for Series II, IIA and III Land Rovers (petrol models), Rover 2000 and 2000 TC manual models, Rover P4, Rover P5 Mark I, IA and Mark III models, Rover part number 551508, Lucas number 35598. 

No to be confused with modern reproduction ones, even ones which may be sold under the Lucas brand. These are made in the UK and are offered at about one third of the current official Land Rover price.

It also fits a wide range of other classic British cars from the 1960s and 1970s

If you have any questions please ask.