I would like to add to Steve Guy’s article about the British military involvement in Russia after the 1917 Revolution.
The British military took the opportunity to use the latest technology of warfare and tactics. Motor torpedo boats went straight from trials off Southampton to the Kronstadt, where they sunk Russian ships. Two Victoria Crosses were awarded for this action. Phosphorous bombs were dropped by the British air force in north Russia — the first time they were used in warfare. The British air force were the first to use machine guns on aircraft against concentrations of Red Army cavalry. British tanks led the force that captured Tsaritsyn (Stalingrad). The Whites issued several thousand medals to British military personnel.
For once American troops were not so keen on a foreign war. In north Russia they had some sympathy for the Bolsheviks, who they likened to Americans fighting the British in 1776. A mutiny led by an American sergeant eventually resulted in a US withdrawal rather than a court martial.