Many thanks for your patience. It is possible that they could advise the new employer of what happened. The issue is that you are still their employee and this happened whilst you were employed by them. So it is still a matter which relates to your employment with them. As such they can include it in a reference to a new employer, even if they have already provided one, meaning they can send an updated reference with details of this.
Whilst there is no legal obligation on employers to provide a reference for past employees, if they choose to do so they will automatically owe them a duty to take reasonable care in its preparation. This requires the employer to be accurate in the contents of the reference and ensure it is based on facts, rather than just personal opinion.
Certain principles have been established through case law over the years and one relevant is from the case of Cox v Sun Alliance Life Ltd where the employer provided a reference that contained details of an employee's alleged misconduct. However, they did not properly investigate these before providing the reference and the employee challenged the information in it. The court decided that an employer will be negligent in providing a reference that refers to an employee’s misconduct unless the employer had carried out an investigation and had reasonable grounds for believing that the misconduct had taken place. So if they did mot investigate the comments, who may have made them, why they have been made, etc then mentioning that in a reference could be negligent.
So if it is obvious that incorrect facts have been relied on, the contents are false or misleading, there may be a potential case for negligence against the employer and this matter could be taken further by seeking compensation in the county court for any damages caused. Also remember that there is no guarantee they will go back to the new employer at all because as far as they are concerned they have already provided a reference and may not be prompted to send a new updated one.
This is your basic legal position. I have more detailed advice for you in terms of the steps you can follow should you need to take this further, which I wish to discuss so please take a second to leave a positive rating for the service so far (by selecting 3, 4 or 5 stars) and I can continue with that and answer any further questions you may have. Don’t worry, there is no extra cost and leaving a rating will not close the question and we can continue this discussion. Thank you