In my opinion it makes for a better understanding and application of our rules to appreciate the raisons d’etre which underlie their prescription. In this regard, the raison d’etre of the rule that leave should be obtained before the issue of an originating summons to be served out of the jurisdiction of the court is well put in Halsbury’s Laws of England (Vol. 37) (4th Edition) at para 171 as follows: ‘Service out of the jurisdiction is recognised as the exercise by the English court of judicial power over a foreigner who owes no allegiance to the United Kingdom or over a person who is resident or domiciled out of the jurisdiction, but is nevertheless called upon to contest claims made against him in England and Wales. However, it is generally accepted that, in accordance with the comity of nations, each nation is entitled, in circumstances permitted by its own laws, to exercise judicial power over persons in other countries; but, of course, the exercise of such sovereign power by the issue and service of judicial process over persons in another country is prima facie an infringement of the sovereignty of the other country.
— O. Ayoola, JSC. Carribean v NNPC (2002) – SC.74/1993