“(1) For the purposes of this Act, any new claim made in the course of any action shall be deemed to be a separate action and to have been commenced— (a) in the case of a new claim made in or by way of third-party proceedings, on the date on which those proceedings were commenced; and (b) in the case of any other new claim, on the same date as the original action. (2) In this section a new claim means any claim by way of setoff or counterclaim, and any claim involving either— (a) the addition or substitution of a new cause of action; or (b) the addition or substitution of a new party; … (3) Except as provided by section 33 of this Act or by rules of court, neither the High Court nor the county court shall allow a new claim within subsection (1)(b) above, other than an original set-off or counterclaim, to be made in the course of any action after the expiry of any time limit under this Act which would affect a new action to enforce that claim. For the purposes of this subsection, a claim is an original setoff or an original counterclaim if it is a claim made by way of set-off or (as the case may be) by way of counterclaim by a party who has not previously made any claim in the action. (4) Rules of court may provide for allowing a new claim to which subsection (3) above applies to be made as there mentioned, but only if the conditions specified in subsection (5) below are satisfied, and subject to any further restrictions the rules may impose. (5) The conditions referred to in subsection (4) above are the following— (a) in the case of a claim involving a new cause of action, if the new cause of action arises out of the same facts or substantially the same facts as are already in issue on any claim previously made in the original action; and (b) in the case of a claim involving a new party, if the addition or substitution of the new party is necessary for the determination of the original action. (6) The addition or substitution of a new party shall not be regarded for the purposes of subsection (5)(b) above as necessary for the determination of the original action unless either— (a) the new party is substituted for a party whose name was given in any claim made in the original action in mistake for the new party’s name; or (b) any claim already made in the original action cannot be maintained by or against an existing party unless the new party is joined or substituted as plaintiff or defendant in that action. …”
“(1) This rule applies to a change of parties after the end of a period of limitation under—” (a) theLimitation Act 1980 … (2) The court may add or substitute a party only if— (a) the relevant limitation period(GL) was current when the proceedings were started; and (b) the addition or substitution is necessary. (3) The addition or substitution of a party is necessary only if the court is satisfied that— (a) the new party is to be substituted for a party who was named in the claim form in mistake for the new party; (b) the claim cannot properly be carried on by or against the original party unless the new party is added or substituted as claimant or defendant; (c) the original party has died or had a bankruptcy order made against him and his interest or liability has passed to the new party.… ”