1949年4月-1950年1月间中国局势发生重大变化，英国对中国共产党、国民党态度发生变化。中国共产党与英国关系呈现由紧张到逐步改善的趋势。英国与国民党关系呈现逐渐恶化的趋势。第二次世界大战后英国因其国力衰落，开始从亚洲进行战略撤退，其对华政策主要以维护其在华经济利益为主，因而解放战争爆发前后，英国采取相对中立政策，避免卷入解放战争，并确立“一只脚踏入”的对华战略，英国与国共双方都有接触。与国民党在战后恢复两国贸易，重建海军等领域有合作。英国与国民党在香港、西藏、对华军售等问题上有着较大矛盾。英国为维护其在解放区利益，便尝试与中国共产党各层级领导人进行接触，中国共产党领导人将美英区别对待，愿与英国发展关系。

1949年4月解放军发动渡江战役前夕，“紫石英”号事件爆发，英国与中国共产党关系一度恶化，但双方都不希望冲突升级，为妥善处理“紫石英”号事件双方加强接触，避免冲突升级。国民党当局对“紫石英”号事件较为关注，希望借此使英国与中国共产党冲突升级。“重庆”号事件后，为防止“灵甫”舰起义，英国提出提前收回“灵甫”舰。经国民党与英国交涉后，“灵甫”舰由上海移防至广州。4月英国在 “灵甫”舰停泊香港时对该舰扣押并收回，使得国民党与英国的关系开始走向恶化。中国共产党方面则争取部分“灵甫”舰官兵起义。上海解放后，英国判断中国共产党将会长期治理上海，应尽可能留在上海并尝试与中国共产党贸易以维护英国在上海经贸利益。国民党为阻止解放区重建，遏制英国对解放区贸易，对上海进行海空封锁，轰炸、扣押英国商船，使得英国在沪损失惨重，英国与国民党关系进一步恶化。中国共产党积极进行反封锁斗争并向英方表示愿与外国发展贸易，推动双方关系发展。随着解放战争战局变化英国将承认新中国提上议程，1949年5月英国国内开始考虑适当时机承认中国共产党。随着解放战争局势变化，《中美关系白皮书》发表，英国意识到蒋介石败局已定，中国共产党将会解放全中国。中国共产党一方面反对帝国主义对华侵略，另一方面表示愿意与世界各国建立外交关系。1949年10月英国确立了承认新中国的政策，1950年1月承认新中国，国民党当局主要通过外交活动阻止英国对新中国承认，但以失败告终。

由此看来，1949年4月-1950年1月英国与中国共产党的关系是向好发展，英国与国民党局的关系逐步走向恶化。

From April 1949 to January 1950, China's domestic situation underwent tremendous changes, and Britain's attitude towards the CPC and the KMT altered as well. The relationship between the CPC and Britain showed a trend from tension to gradual improvement, while the relationship between Britain and the KMT went from bad to worse. After the Second World War, Britain began to retreat from Asia due to the decline of its national strength, and its policy on China was mainly to safeguard the economic interests. Therefore, before and after the outbreak of the War of Liberation, Britain adopted a relatively neutral policy to avoid being involved in the war. Also, it established the strategy of "a foot in the door" and contacted both the KMT and the CPC. After the War of Resistance Against Japan, Britain and the KMT cooperated in restoring the bilateral trade, rebuilding the navy and other aspects. However, great contradictions existed between the two sides on the issues of Hong Kong, Tibet and arms sales to China. In order to protect its interests in the liberated areas, Britain tried to get in touch with the leaders of all levels of the CPC. And the leaders of the CPC treated the United States and Britain differently and showed their willingness to develop relations with Britain.

In April 1949, the Amethyst incident broke out on the eve of the campaign to cross the Yangtze River by the PLA, and thus the relationship between Britain and the CPC once deteriorated. However, both sides did not want to escalate the conflict. To properly handle this incident, both sides strengthened contacts to avoid its escalation. The KMT authorities paid much attention to this incident, hoping to upgrade the clash between Britain and the CPC. In the wake of the CHUNG KING incident, Britain proposed to take back LING FU in advance to prevent its uprising. Through the negotiations between the KMT and Britain, LING FU was transferred from Shanghai to Guangzhou. In April, Britain seized and recovered LING FU when it was berthed in Hong Kong, which worsened the relationship between the KMT and Britain. On the other hand, the CPC strove for the uprising of some officers and soldiers on LING FU. After the liberation of Shanghai, Britain judged that the CPC would govern this city for a long time, so it must try its best to stay in Shanghai and trade with the CPC for safeguarding its commercial interests here. To prevent the reconstruction of the liberated areas, the KMT contained British trade in these areas, blockaded Shanghai by sea and air, as well as bombed and impounded British merchant ships. All of these measures made Britain suffer enormous losses in Shanghai and worsened the relationship between Britain and the KMT further. The CPC actively fought against the blockade and expressed to the British side its willingness to develop trade with foreign countries and promote the advancement of bilateral relations. As the situation of the War of Liberation evolved, Britain put the recognition of New China on the agenda. In May 1949, Britain began to consider recognizing the CPC at an appropriate time. With the change of the situation in the War of Liberation and the publication of The China White Paper, Britain realized that Chiang Kai Shek was doomed to failure and that the CPC would liberate China. At the same time, the CPC expressed its willingness to establish diplomatic relations with foreign countries while sticking to the anti-imperialist stance. Britain established the policy of recognizing New China in October 1949 and recognized it in January 1950. The KMT authorities mainly prevented Britain from recognizing New China through diplomatic activities but ended in failure.

In view of this, from April 1949 to January 1950, the relationship between Britain and the CPC was gradually improving, while that between Britain and the KMT authorities deteriorated.