Is there an alternative to a performance disciplinary process?
Yes, there is. The performance disciplinary route will normally require your employer to give you a number of warnings and opportunities to improve. This process could take many months.
The relationship with your employer has often broken down by the time is reaches the performance disciplinary stage and it may be that your employer will be receptive to your departure as a negotiated exit on mutually agreed terms. This usually would result in your entering into a compromise agreement in which you would be paid a lump sum package in return for giving up your employment rights.
Many employees prefer this route rather than the rather tortious performance plan route and it can be a sensible solution for both parties.