The law says that a lack of capability is one of the potentially fair reasons for dismissing someone. The allegation, therefore, should be taken very seriously.
Capability in law is assessed by reference to 'skill', 'aptitude', 'health' or any other 'physical' or 'mental' quality. Your employer must state the reason and give evidence as to why it is believed that you are not capable of doing your job. The employer should also give you time to improve and provide necessary training to help you meet the original standards.
If you have recently joined your organisation, have taken on new responsibilities, or have been promoted, it may be that these circumstances have given rise to your employer's perception. If there is some substance to this view it might be that you wish to explore, with your employer, opportunities for further development or training that will help you meet the demands of the job, or perhaps request your employer to give consideration to your doing an alternative job to which you may be better suited.
If the perceived lack of capability has anything to do with disability then the law requires your employer to consider making 'reasonable adjustments' to enable you to perform. If it is not already aware of it, your disability should be drawn to your employer's attention. Also, if you wish, you can make suggestions as to what reasonable adjustments would help you fulfil your duties.
