All correspondence should now be in writing (or at least email) so that you have a record of anything said and any accusations made. People will be cautious of accusing you of anything in writing. You can copy your emails to a senior person and be open about that. Never say anything in anger and never accuse or criticise. Simply state the facts in a dispassionate way. **For example** You could offer in writing to take a similar test whilst being observed. It is unlikely that you will be taken up on this but the fact that you have offered will make them think twice. If there is any disciplinary action, you can then point out that you were willing to demonstrate your strategy. ___________________________________ **Important** Never act in the heat of the moment. Take your time, stay polite but be insistent. Do not give up.