Key will not go in the ignition

[Laserchip]

Hello, I have a 57 plate Passate 1.9 SE TDI Estate. Today the key has decided not to go into the ignition. It goes about half way in and can not go any further. It looks like there is a piece of black plastic inside the ignition which is either in some kind of lock position the preventing the key going any further. Maybe like some kind of immoblizer. Hence i can't start the car. Would be interested if anyone else has come accross this problem and also whether this could be a manufactuing defect with the design of this car or ignition system.
Regards
Gareth