Final answer:
Since Ukraine's independence in 1991, the UK and western allies have provided diplomatic support, economic aid, and after Russia's 2022 invasion, significant military support to help defend Ukraine's sovereignty. Finland's NATO membership in 2023 exemplifies the West's strategic counter to Russian expansion.
Step-by-step explanation:
The main type of support that the United Kingdom (UK) and other Western allies have provided to Ukraine since its independence in 1991 has largely been diplomatic and economic in nature. Following the dissolution of the Soviet Union, Western countries have encouraged and assisted former Eastern bloc nations, including Ukraine, to adopt democratic reforms and integrate with European and transatlantic institutions like the European Union (EU) and the North Atlantic Treaty Organization (NATO). This support intensified significantly in response to Russia's annexation of Crimea in 2014, with increased sanctions, political backing, and non-lethal military aid. However, the nature of assistance changed dramatically after Russia's full-scale invasion of Ukraine in February 2022. During this period, the UK and allied Western countries provided extensive military support, including lethal aid, to Ukraine, alongside continued sanctions against Russia and diplomatic efforts to isolate it internationally. Importantly, on April 4, 2023, Finland became the newest member of NATO, illustrating a traditional approach to counteract Russian expansionism. Western allies' relationship with Ukraine is marked by a commitment to defend the principles of sovereignty and territorial integrity in the face of aggression.