Three months from the termination of employment is the deadline in which employees must make unfair dismissal claims. After this date, the claim may be barred unless there are found to be special circumstances that prevented them from presenting their claim within that timeframe. The deadline may also be extended in some discrimination cases.
If you receive an ET1 form from a former employee outside of this time frame, you should still complete and return your ET3 form, but state clearly that the claim has been made out of time as part of your defence. You should also request a preliminary hearing to determine why it was made out of time and how this affects the claim. The claim may still go to Tribunal for a number of reasons even if it was made out of time.