Yes and no. If it becomes necessary, you would be referred to solicitors with a legal aid contract who would do virtually all the work, although you will obviously have to liaise with them about evidence etc.
However, the vast majority of cases never proceed beyond the original pre-action letter. If, for instance, a local authority has missed a statutory deadline, it will be well aware that it has no defence to a JR claim and will not want to risk becoming liable for its own and the claimant’s costs.