"As a general rule the court will not exercise its discretion underCPR 25 to make an order for security for costs of the claim if the same issues arise on the claim and counterclaim and the costs incurred in defending that claim would also be incurred in prosecuting the counterclaim."
"The trend of authority makes it plain that, even though a counterclaiming defendant may technically be ordered to give security for costs of a plaintiff against whom he counterclaims, such order should not ordinarily be made if all the defendant is doing, in substance, is to defend himself. Such an approach is consistent with the general rule that security may not be ordered against a defendant. So the question may arise, as a question of substance, not formality or pleading: is the defendant simply defending himself, or is he going beyond mere self-defence and launching a cross-claim with an independent vitality of its own."