Your employment lawyer will advise you of any facts and evidence you need to collect and document. 

For example, if an employee is taking you to an employment tribunal, you must have evidence to defend the claim, or you are likely to lose. 

How to Gather the Evidence

You must keep records of as much evidence as possible to help you defend your tribunal claim.  Make a diary and keep notes of all related conversations you have with your employee.  Save all memo’s, letters, minutes from meetings, emails and attendance records.