l have got a Peugeot 306 with keypad immobiliser.The membrane under the number 1 has deteriorated and l cannot put in relevant number to start car. All other numbers are ok just the number 1.Has anyone got any suggestions regarding my problem.

Send it back to the manufactuor, or call them. They're bound to replace it, probably.
Unless you can change the code without pressing the 1 key, in which case do that.

the codes on the 405 is are in the keypad so its simply a case of changing the keypad for one from a breakers yard that you know the code of. Not sure if its the same on the 306 though. Its a job for a specialist or dealership i'm afraid.

Anyone into electronics may be able to repair the keypad?

Edit: Just spoke to a mate that specialises in Peugeots, if you get another keypad from a breakers yard it will work with your same code.

call an auto spark, or do an internet search. these keypads are a pain. they will tell you what wires to join to bypass the keypad.

l have removed lots of these from customers cars and have fitted a Alarm/ immobiliser unit which Also give the car remote locking.