The nature of the Locarno Treaty was the assumption of an obligation by Great Britain and Italy to both Germany and France. It was apparently greeted with much jubilation because unlike the other treaties, it was an "open treaty" which meant that it was not directed against any particular state but rather an unknown aggressor within a defined area.
The Treaties of Guarantee signed by the Americans and the British were aborted - President Wilson and Lloyd George induced Clemenceau to drop the demand for permanent occupation of the Rhineland. From the first months of peace, the French were wary of a possibility of new attacks and they were pretty sure where these attacks would come from. They were concerned mainly with the security against invasion. The thesis set out by Clemenceau was that a superior military force would have to be available at the very onset of hostilities, and not at a gradual pace as this would be to no avail. Assistance given gradually would leave France to bear the brunt of the attack alone.
Jordan goes on to claim that the British did not want to get involved in any guarantees that involve them in parts of Europe that they were not interested in (particularly the east).
The British and French could not reach an agreement as to what the definition of security was. For France, it was the adequacy of military preparation. The British on the other hand did not have to fear invasion because of the Channel but rather entanglement in a war of European origin.
Jordan also says that the French were concerned with the degree of security provided by the League (of Nations) according to the Covenant. Two of the articles of the Covenant - 10 and 16 - which determined the character of the League as a security organization, were not of French origin. Article 10 was to provide a guarantee of "the territorial integrity and existing political independence" of all member states.