In older vehicles this is done via an Ignition Distributor, with newer vehicles using Multi-Outlet Coils with Ignition Leads connected directly to the Spark Plugs. HT Leads, ignition cable, plug leads, ignition wires.
Genuine Intermotor Ignition Cable Kit - 73780
Genuine Intermotor Ignition Cable Kit - 73833
Genuine Intermotor Ignition Condenser - 34570
Genuine Intermotor Ignition Condenser - 33950
For Reliant Robin 850 Genuine Intermotor Ignition Condenser
Genuine Intermotor Ignition Condenser - 34600