Employers use disciplinary procedures to resolve issues related to the performance or conduct of their employees which isn't up to the expected standard and to encourage improvement. They should cover notification of the employee that there is a problem and also what steps the employer will take after notification to make sure the problem is dealt with.
A disciplinary procedure is sometimes the best way for your employer to tell you when something is wrong. It allows them to explain clearly what improvement is needed and should give you an opportunity set out your side of the situation.
Your employer must put their disciplinary procedure in writing, and make it easily available to you (e.g. by giving details in the staff handbook). It should include the rules, what performance and behaviour might lead to disciplinary action, and what action your employer might take.
The Advisory, Conciliation and Arbitration Service (Acas) produce a code of practice on disciplinary procedures. You can't take your employer to an employment tribunal just because they haven't followed the code, but an employment tribunal can impose an uplift of up to 25% of any award where there has been an unreasonable failure to comply with any provision of it.
If your employer has laid down a disciplinary procedure that forms a part of your contract then you could sue for breach of contract if they haven't followed it.
During a disciplinary procedure, if your employer does anything which seems unreasonable you should tell them (in writing) and suggest ways to solve the problem. They may decide to carry on the procedure anyway, in which case, you might decide to use the issue as grounds for an appeal.
If you face disciplinary action, and aren't sure what to do, you can always get advice about your rights. Acas and your local Citizens Advice Bureau (CAB) provide free and unbiased advice, and you may be able to get help from a union if you're a member.
Before taking formal disciplinary action, your employer may try and raise the matter informally with you first of all. This is often a good way of resolving a problem quickly.