The ignition key has the usual buttons to open and lock the car, also a key to go in the ignition. The key locks and unlocks the car as usual, but when I try to put the key in the ignition lock, it refuses to go however hard I push it.

I have tried changing the key battery, but to no avail. The spare key continues to open the car and operate the ignition to start the car as normal.

I suspect that the circuits contained in the original key which hold the code for my own car have somehow got confused. The main dealers tell me that they have never heard of this problem, and can only suggest checking the ignition system, no doubt at considerable expense. But the spare key works fine, suggesting that the problem is with the original key, not the ignition system.

Have you any heard of this problem, and if so, have you any ideas for dealing with the original key so that it works should I need it in the future?