Thank you very much for clarifying. First of all, I am sorry to hear about the issues you have experienced in your situation.
A dismissal, without prior warnings, should only happen if there has been a case of gross misconduct. This is something serious enough to justify instant dismissal, although there is no specific list of offences and potentially anything can qualify, if it is serious enough.
A GDPR breach can amount to gross misconduct but the circumstances of the offence should also be considered. For example, factors that would be relevant include: what data was breached and what was the scale of the breach; how sensitive was the data; what impact it had on the employer or their customers, suppliers, staff, etc; did the employee not follow policies and procedures in the process; were there clear steps that were missed that would have prevented this; what caused the error and are there any mitigating factors.
There are many other factors that could be relevant but this is just an idea of what an Employment Tribunal may look at if they are faced with an unfair dismissal claim because of such a dismissal.
In the end, all that can be done is defend the allegations to the best of your ability, but if a dismissal occurs then you have to look at an unfair dismissal claim in the Employment Tribunal.
Before a claim can be made against the employer in the Employment Tribunal, the affected employee would be required to participate in a process known as ‘early conciliation’, which is administered through the Advisory Conciliation and Arbitration Service (ACAS).
The purpose of this process is to allow ACAS to mediate between the employee and their employer to agree on an out-of-court settlement in order to avoid the need for legal action in the Employment Tribunal. The employer does not have to engage in these discussions and the process is voluntary for them. If they refuse to participate, or the conciliation is unsuccessful, the employee will be issued with a certificate by ACAS allowing them to make a claim.
However, if a settlement is reached, the employee would officially agree not to proceed with the claim in return for the agreed financial settlement. Other terms can also be included as part of the settlement, such as an agreed reference.
In order to initiate the early conciliation procedure, ACAS must be contacted, either online by filling in the following form (https://tell.acas.org.uk/find-a-solution-to-your-employment-dispute), or by phone on 0300(###) ###-#### They will explain the process and what happens next and get the ball rolling on your behalf.
If the early conciliation process was not successful, ACAS have issued a certificate to confirm that and you still wanted to make a formal claim in the Employment Tribunal, the claim can be initiated via the following link: