Can my boss stop me putting up tinsel and baubles just because she thinks it makes the office look unprofessional?

Well that is her opinion and there is little you can do about it. If it's an office where the public have access, try arguing that Christmas decorations are good for business. If Christmas decorations are put up just be a little safety conscious. Try where possible to use non-flammable items and don't have them hanging in areas where they might be a fire risk. Oh, and don't stand on a chair which is on desk just so you can get the mistletoe in the centre of the room or it may be more than a heart that is broken this Christmas.

Your boss may well use the argument that it’s a health and safety risk. If she does allow you to decorate, we'd suggest reading our free safety checklist for office decorations. You can download it here.