how to turn of renaul megane immobiliser ?

The fob key I have will not turn off the immobiliser on my wifes 1997 renault megane. I can get it started by entering the four digit code manually. Is there any way I can get rid off the immobiliser altogether as I do not want to pay 200 euro for a new key as when the insurance and nct is up in 6 months I will be scrapping the car.

Mark (Dublin)
January 2010