Mitsubishi Repair: Warning alarm when ignition started and when keys removed

Question
I am getting a constant alarm lasting 30 sec when the ingnition is turned on and after its switched off any idea of what this could be ( Mitsubishi Colt 61 plate)

Answer
Susie,
I do not have any experience with that particular car, but I have encountered similar issues with car alarms acting a wonky at time.  It seems as if your car alarm is reacting to perhaps the way it was last disarmed and is not subsequently being disarmed.  You can sometimes trick the alarm to disarm by unhooking the negative battery terminal, inserting the key into the ignition and turning it on, then reattaching the negative battery terminal. This will often cause the alarm to disable until next time it is set and allow you time to get the car in for service to determine what is going on with the remote (or alarm if the problem is not in the remote itself).
Good luck!