British forces are preparing to board and detain ships in Russia's shadow fleet following the prime minister's approval for military action. This is aimed at cutting off funding for Russia's war in Ukraine. The operation is expected to commence soon, with training already completed. The government believes a significant portion of Russia's oil is transported by these sanctioned vessels, and military planners are monitoring ship-tracking technology to identify targets. The situation is described as increasingly volatile and dangerous, with political leaders emphasizing the need for action against Putin's operations.