The expression "implied undertaking" is thus merely a formula through which the law ensures that there is not placed upon litigants, who in giving discovery are suffering "a very serious invasion of the privacy and confidentiality of [their] affairs", any burden which is "harsher or more oppressive ... than is strictly required for the purpose of securing that justice is done". To that statement by Lord Keith of Kinkel of the purpose of the "implied undertaking" may be added others. In Riddick v Thames Board Mills Ltd [[1977] QB 881 at 896] Lord Denning MR said:
"Compulsion [to disclose on discovery] is an invasion of a private right to keep one's documents to oneself. The public interest in privacy and confidence demands that this compulsion should not be pressed further than the course of justice requires. The courts should, therefore, not allow the other party - or anyone else - to use the documents for an ulterior or alien purpose. Otherwise the courts themselves would be doing an injustice".
In Harman v Secretary of State for Home Department [[1983] 1 AC 280 at 300] Lord Diplock said:
"The use of discovery involves an inroad, in the interests of achieving justice, upon the right of an individual to keep his own documents to himself; it is an inroad that calls for safeguards against abuse, and these the English legal system provides ... through its rules against abuse of process and contempt of court".
In Watkins v A J Wright (Electrical) Ltd Blackburne J said:
"In my judgment, a serious inroad into [the safeguards referred to by Lord Diplock] and, therefore, into the utility of the discovery process in the just disposal of civil litigation would occur if it were open to a litigant (or his solicitor) to enjoy the fruits of discovery provided by the other side, but avoid the risk of committal for contempt for acting in breach of the countervailing implied obligation on the ground that he was unaware of the existence of the undertaking. I take the view that it does not lie in the mouth of a person to plead ignorance of the legal consequences of the discovery process".
To speak in terms of "undertaking" serves:
"a useful purpose in that it confirms that the obligation is one which is owed to the court for the benefit of the parties, not one which is owed simply to the parties; likewise, it is an obligation which the court has the right to control and can modify or release a party from. It is an obligation which arises from legal process and therefore is within the control of the court, gives rise to direct sanctions which the court may impose (viz contempt of court) and can be relieved or modified by an order of the court".
[Footnotes omitted.]