After four years of secrecy negotiations, the United Kingdom and the United States finally published on 7 October 2019 the text of their data exchange agreement, which aims to facilitate cross-border access to electronic data for the purpose of combating serious crime. This long-awaited agreement is the first of the executive agreements provided for in the CLOUD Act. As I rightly said, "it is essential to offer not only a window into the approach of the United States and Britain, but also probably a fundamental plan for other agreements that may follow." Indeed, the United States and the European Union have recently begun negotiations to conclude an agreement in this area, while the United States and Australia have also announced that they have started similar negotiations. Firstly, this article attempts to explain the fundamental mechanisms of the agreement between the United Kingdom and the United States - without, of course, claiming an exhaustive presentation of all the topics covered. This is done using two graphs that indicate when and how (and under what conditions) data can be requested from country custodians by both parties to the agreement and when other more traditional means of access to electronic evidence, such as.B mutual legal assistance (GwG) contracts, should be used (Part II). Next, this document will express a number of thoughts, comments and questions about the content of the agreement. It considers that while the agreement contains some useful elements that could make it possible to review some of the boxes of the negotiating mandate that was granted to the European Commission in June 2019, some other issues remain unclear and uncertain, while others are clearly problematic. They raise a number of important issues that need to be addressed in order to better understand the impact that this agreement could have on the ongoing negotiations between the EU and the US and, more generally, on EU law (Part III). The current mutual legal assistance procedure can take up to two years, but the agreement will significantly reduce this period while protecting privacy and strengthening civil liberties. The landmark agreement was reached by U.S. Attorney General William P. Barr and British Home Secretary Priti Patel signed at a ceremony at the residence of the British ambassador in Washington, D.C. .