Clerks are the people at the tribunal who handle the administration on the day of the hearing: they take your name when you arrive, collect bundles and witness statements for the tribunal and the witness table, ask whether you want to affirm when you give your evidence, or swear on a holy book, take you to your tribunal room when the tribunal is ready to begin, and so on. They aren’t lawyers, so you can’t expect them to give you legal advice – but they will have a lot of practical information about how the tribunal works, and mostly they are pleasant and helpful. You can ask them, for instance, if you need to pass a message through to the employment judge – for instance to ask for more time to finish negotiating; or if you need to know where the nearest print shop is (they won’t be allowed to do photocopying for you unless told to by an employment judge); or whether the other side has arrived at the tribunal yet; or to find out if there’s a room you can use to meet with the other side for negotiations.
First thing in the morning, until about 10 am, there will be a clerk on the reception desk at most tribunals. At other times, if they are not around, you can probably contact them using the telephone on the reception desk – there will be instructions on or near it about which extension to call.