1926年9月，因与四川军阀杨森发生冲突，英国军舰悍然炮轰万县，造成当地众多民众的直接伤亡和财产损失。这是北伐时期英国武力干涉中国的代表性事件，被称为“万县惨案”。

万县惨案的发生，是必然性与偶然性相互作用的产物。一方面，北伐战争以英国的核心势力范围——长江流域为主要战场，并将英国作为帝国主义的代表予以攻击。为了避免在华利益和地位受到威胁，英国决定动用武力震慑中国的军事行动和反英运动。另一方面，中英在长江上游素有航运矛盾，为英国出兵提供了绝佳的借口。

万县惨案的交涉引起了四川地方军阀、北京政府、南方国民政府和英国的多方因应。初期因循的领事与军阀“地方外交”的路径受阻后，北京政府的介入不仅没有成功提升自身的政治威望，反而遭到了公众舆论的反复攻讦。国共两党继而以“革命外交”的方式主动参与其间，通过开展民族主义的政治宣传、发起群众运动，将中英的外交问题转变为南北之争的内政问题，以此声援北伐战争。

由于万县惨案发生的时间和地点的特殊性，事件追责及善后赔偿问题没有彻底得到解决。但在交涉过程中，各方政治势力的互动关系，既反映出国际因素影响下，北京政府的衰微与国民政府的壮大，也有力地推动了英国对华政策的调整和中英关系的逐渐缓和。

In September 1926, due to a conflict with the Szechuan warlord Yang Sen, the British warships brazenly bombarded Wanhsien, causing direct casualties and property losses to many local people. This was a representative event of British armed intervention in China during the Northern Expedition, known as the “Wanhsien Incident”.

The occurrence of the Wanhsien Incident is the product of the interaction between necessity and chance. On the one hand, the Northern Expedition took the Yangtze River Valley, the core sphere of British influence, as the main battlefield, and attacked Britain as the representative of imperialism. In order to avoid the threat to its interests and status in China, Britain decided to use force to deter China's military actions and anti-British movements. On the other hand, China and Britain have always had shipping contradictions in the Upper Yangtze, which provided an excellent excuse for Britain to send troops.

The negotiations over the Wanhsien Incident provoked a multi-pronged response from local warlords, the Peking Government, the Nationalist Government, and the British. After the initial path of "local diplomacy" between consul-generals and warlords was blocked, the Peking Government's intervention not only failed to enhance its own political prestige, but was repeatedly criticized by public opinion. The Kuomintang and the Communist Party then took the initiative to participate in the process of "revolutionary diplomacy". By carrying out nationalist political propaganda and launching mass movements, the Sino-British diplomatic issue was transformed into an internal affair between the North and the South, in support of the Northern Expedition.

Due to the particularity of the time and place of the Wanhsien Incident, the issue of accountability and compensation for the aftermath of the incident has not been completely resolved. However, in the process of the negotiations, the interaction between the political forces of various parties not only reflected the decline of the Peking Government and the growth of the Nationalist Government under the influence of international factors, but also effectively promoted the adjustment of British Policy in China and the gradual calming of Sino-British relations.