Rule 7 Evidence in mitigation of damages for libel or slander

In an action for libel or slander, the defendant shall not, without leave of [^f1 the judge or district judge as the case may be], give evidence in chief, with a view to mitigation of damages, as to the circumstances in which the libel or slander was published or as to the character of the plaintiff, unless before the beginning of a period of seven days ending on the day of the hearing he furnishes particulars to the plaintiff of the matters as to which he intends to give evidence.