"The court may order a person to be added as a new party if – (a) it is desirable to add the new party so that the court can resolve all the matters in dispute in the proceedings; (b) there is an issue involving the new party and an existing party which is connected to the matters in dispute in the proceedings, and it is desirable to add the new party so that the court can resolve that issue."
"The Court recognises that occasionally the facts on which a claim against another party might be based might not emerge until after particulars of claim have been served. Consequently, in general the court will permit the addition of a new party if it is likely to assist the court in the efficient resolution of all maters in dispute."