The American M4 Sherman is the best known, most widely used tank of the Second World War. It is also the most controversial. Was it the all-American tank that won the war or a completely under-designed death trap? We go to the Isle of Wight Military History Museum, where Dave Arnold and his crew are about to try something no one else has ever done before. They are going to chop two destroyed Shermans in half to piece together one good one. If they can pull it off it will be a testament to the most revolutionary aspect of the Sherman's design – American-style production engineering allowed for production on a massive scale. It will show just why the Sherman, despite its flaws, remains one of the most important tanks ever made; and one of the many reasons why the Allies won the War.