(1)Where after the institution of a suit, a new plaintiff or, defendant is substituted or added, the suit shall, as regards him, be deemed to have been instituted when he was so made a party:Provided that where the court is satisfied that the omission to include a new plaintiff or defendant was due to a mistake made in good faith it may direct that the suit as regards such plaintiff or defendant shall be deemed to have been instituted on any earlier date.
