I have a Perodua Nippa car and only one key. 
Its too expensive to buy a spare. How can I safely remove or bypass
the ignition immobiliser unit so that my key operates just as a
mechanical (non electronic or "chipped" key) for ignition. (I could
then have the key copied for only a few pounds each. The door locks
are entirely manual)I am not worried about car theft

anytime you replace the factory alarm with an aftermarket alarm you
have to purchase a by-pass module also. This would serve the same for
your needs. ($69USD) Then you place your key tied into the electric
system of the car so that it is always bypassed. I'm sure that their
are other ways too...