In that conclusion, he also attempted to draw an analogy with entire contractual clauses, insofar as both parties had to obtain contractual security on the agreed terms. Lord Briggs, however, found that there was no distinction between oral amendment clauses and entire contractual clauses, as they did not attempt to attach it to their future behaviour. According to Lord Briggs, this party may persist as long as a party wishes to maintain an oral amending clause (as it does with any clause), unless all parties agree to cancel it- although it concludes that if the parties agree orally to amend the content of their contract. should no longer be implicitly stated that they have also agreed to waive a clause without an oral amendment, unless such involvement is necessary. Overall, according to the majority`s arguments, the parties agree that oral derogations are not valid and not prohibited. Therefore, the natural conclusion that such a clause was not that the parties intended to waive it, but that they would have neglected it. On the other hand, when they had the clause in mind, but acted anyway, “they were courting nullity with their eyes open.” However, in Rock Advertising Limited v. MBW Business Exchange Centres Limited, the Supreme Court confirmed that an alleged contract amendment was not valid if it contravened a non-oral amendment provision in the agreement. Finally, it should be noted that the effects of the decision have yet to be developed. The Supreme Court has confirmed that the risk that a party may react to the diversity of the treaty, but then cannot be imposed, is mitigated by different Estoppel doctrines, although it remains unclear how this would be applied in practice. One can imagine a trade policy treaty that was amended orally in violation of a non-oral amendment clause, and the parties acted on the basis of the amendment for a number of years. It seems surprising that their ongoing and modified relationship could only be explained on the basis of Estoppel. In general, such a policy should apply, regardless of the doctrine used, regardless of the extent to which the majority`s decision is influenced by political issues.
In this regard, it seems strange that estoppel can confirm an amendment that has been overturned by contract law. In Rock Advertising Limited v. MBW Business Exchange Centres Limited  UKSC 24, the Supreme Court confirmed that an alleged oral modification of a contract is not valid if it does not contravene a verbal amendment to the agreement.