English abstract Material change of circumstances and the impossibility of performance within the Czech and English legal system Civil law in the Czech Republic is based on a so-called principle pacta sunt servanda which means that parties are bound by the contract and should perform in accordance with it. It may happen, however, that unexpected supervening event substantially change the circumstances after the formation of a contract to the extent that it become impossible to perform the contract or it makes performance for affected party so burdensome that it will lead the party to the economical destruction. Such a change may lead to situations that to hold the affected party to fulfil its promise would be unjust and contrary to morality. Therefore, Czech Civil Code contains few provisions based on which court may terminate the contract or adjust the contract to restore equilibrium of the performance. Thesis focuses on two of those provisions, namely impossibility of performance and impracticability of performance. Thesis describes relevant legal institutes and doctrines, development of case law, analyze past and current Czech Civil Code and compare it with English case law and international and European soft law. After introductory chapter, chapter two describes relevant principles of civil law and...

This thesis attempts to critically and comparatively analyse the doctrine of exemption/frustration /force majeure under the United Nations Convention on the Contract for International Sale of Goods (CISG) the UNIDRIOT Principles of International Commercial Contracts (UNIDROIT) and the English Law. The doctrine of exemption/frustration/force majeure is very important in the area of contract and commercial law, it is a doctrine deeply rooted in fairness and allows a party to be excused from performing an obligation in a contract if at the conclusion of the contract an inhibition beyond the foreseeable control of the party happens to render the performance of the contract impossible. However, it is not easy to effectively streamline this doctrine and properly determine its applications. It has been observed in this thesis that, the doctrines of exemption/frustration /force majeure are not exactly the same; this thesis explores in details severally and jointly the various differences and similarities in the interpretations and applications of these impossibility doctrines. For instance, the open and flexible use of words in the definition of this doctrine under the CISG and the UNIDROIT Principles left much to be desired. Thus, it is one of the succinct arguments of this thesis that couching international law in loose words will work against the uniformity of application of this law, due to the different interpretations national law courts will be subjecting it to. This among other issues retarded the growth and development of the doctrine of exemption and force majeure. Furthermore, English law stance on the doctrine of frustration which can be gleaned from both the Sale of Goods Act of 1979 and the Common law are far from being adequate and need to be updated. This thesis therefore incisively laid bare the applications, interpretations and way forward for the doctrine of exemption/frustration/force majeure under the legal instruments of focus of this work. The thesis also comparatively compares the relationship between the doctrine of frustration/force majeure/exemption and other related doctrines like mistake, termination, avoidance, risk, and hardship. The thesis is concluded with a Draft Model Frustration Clause (DMFC) which is an attempt to rise above the status quo doctrine of frustration in the extant laws and develop a frustration clause that will be able to provide answers to the many flaws that trail these laws.