英國外交政策向以彈性著稱，其為西方國家中第一個宣布承認中華人民共和國政府，然而由於聯合國中中國代表權席位的問題，以及英國仍然維持與台灣的關係（即使是非官方的），使得英國與中共之間的正式外交關係一直到1972年方才確定，而英國方於同年關閉在台灣淡水的領事館。本文之目的乃在觀察英國的彈性外交作爲，特別是其在處理台海兩岸之間關係上所展現的現實性。首先，本文將再檢視以1953年Civil Air Transport Inc. v. Central Air Transport Corporation案爲首的諸項判例，藉此觀察英國在處理國際法議題中關於政府承認回溯效力問題之態度。其次，英國行政部門在處理對台關係時，其所建立的若干不同性質的機構也是本文所欲觀察的對象，這些機構在實質上維繫英國與台灣之間的關係。本文作者認爲由於英國執著於傳統國際法的規範，使得英國與台灣之間仍難建立正式的外交關係。然而，台灣是一個民主、法治、尊重人權、文明進步的國家，若能持續維持此一特色，則在持續與英國的交往上，將可處於有利之局面。

United Kingdom was the first western country of recognizing the government of the People's Republic of China when the latter established in October 1949. However, due to the issue of Chinese seat in the United Nations and the relations between the UK and the government of the Republic of China (Taiwan), both the UK and the PRC did not establish their official diplomatic relations until 1972 when the UK removed its consulate in Tamsui, Taiwan. This paper is going to observe the UK's diplomatic flexibility especially in dealing with the two sides of the Taiwan Strait. Firstly, the case of Civil Air Transport Inc. v. Central Air Transport Corporation (1953) was re-examined so that the consideration of retroactivity of the principle of continuity in state succession could be perceived. Secondly, some of the developments made by the administrative section of the UK were analyzed, such as different organs and mechanism were established so that the substantial relations, although still unofficial, could be maintained. The author concludes that it is difficult to established official relations between Taiwan and the UK owing to the latter's strict perspectives on related principles of the international law. Nonetheless, it is still practicable to say that both sides could improve their relations if Taiwan could demonstrate its improvement on democracy, liberty, and human rights protection.