conquered Belgium and France. It was neutral until Germany suddenly invaded Belgium and France. Britain declared war becoming an ally of France and Russia against Germany and Austria. The alliance lasted when the February 1917 Revolution in Russia overthrew Tsar Nicholas II and the Russian monarchy. However When the Bolsheviks under Lenin took power in November, they made peace with Germany—the Treaty of Brest-Litovsk was in effect a surrender with massive loss of territory. Russia ended all diplomatic and trade relations with Britain, and repudiated all debts to London and Paris. The British supported the anti-Bolshevik forces during the Russian Civil War, but they lost, and Britain restored trade relations in 1921. British–Soviet relations Interwar period In 1918, with the German Army advancing toward Moscow in Operation Faustschlag, the Russian Soviet Federative Socialist Republic under Lenin made many concessions to the German Empire in return for peace. The Allies felt betrayed by the Treaty of Brest Litovsk signed on 3 March 1918. Towards the end of World War I, Britain began to send troops to Russia to participate in the Allied intervention in the Russian Civil War which lasted up to 1925, aiming to topple the newly-formed socialist government the Bolsheviks had created. As late as 1920, Grigory Zinoviev called for a "holy war" against British imperialism at a rally in Baku. Following the withdrawal of British troops from Russia, negotiations for trade began, and on 16 March 1921, the Anglo-Soviet Trade Agreement was concluded between the two countries. Lenin's New Economic Policy downplayed socialism and emphasised business dealings with capitalist countries, in an effort to restart the sluggish Russian economy. Britain was the first country to accept Lenin's offer of a trade agreement. It ended the British blockade, and Russian ports were opened to British ships. Both sides agreed to refrain from hostile propaganda. It amounted to de facto diplomatic recognition and opened a period of extensive trade. Britain formally recognised the Union of Soviet Socialist Republics (USSR or Soviet Union, 1922–1991) on 1 February 1924. However, Anglo-Soviet relations were still marked by distrust and contention, culminating in a diplomatic break in 1927. Diplomatic relations between the two countries were severed at the end of May 1927 after a police raid on the All Russian Co-operative Society whereafter Conservative British Prime Minister Stanley Baldwin presented the House of Commons with deciphered Soviet telegrams that proved Soviet espionage activities.For an