Nellie o98 got it spot on, having been through disciplinary etc myself, (also on trumped up excuses) I would add that its very important for you to have a representative alongside you, I chose someone that I didn't know all that well but he had always seemed to be very sensible, and good at his job. He kept me calm, and asked for breaks in the meeting so that we could confer, and calm down. The industry I worked in got rid of all their older employees, the only people over 50 were management grades or cleaners! It is a thing, and so is looking out for the replacement before getting rid of the staff member in question. You can't fight your dismissal on those grounds though, you have to put all that aside in your mind, and fight it under grounds of unfairness, or incorrect procedure. They will get rid of you if thats in their minds, possibly not on this occasion, this time you will get a written warning with an 'instant dismissal if anything else comes to light' warning, so they are setting the scene and seen to be following procedures. Good luck, if all else fails you could ask if they are wanting to make you redundant? Sacking you saves paying out redundancy payments, and they just have to change the job title of your 'replacement' and then give them extra responsibility after your role is no long required.