A number of friendlies and non-competitive derbies took place during the First and Second World Wars. In total, 33 matches were played between the teams in Wartime Leagues. They both fielded severely depleted sides of juniors, reserves and non-professionals, playing 14 games in the London Combination between 1915 and 1919. West Ham won nine, Millwall three and two were drawn. After the First World War, the Football League was reintroduced in England by The Football Association and West Ham joined the Second Division for the 1919–20 season. Millwall joined the inaugural Third Division in the 1920–21 season, in the Football League expansion of 44 clubs to 66. In 1926 a general strike was observed by workers around the Royal Docks, the majority of whom were West Ham supporters. An unsubstantiated story states that Millwall-supporting shipyard workers of the Isle of Dogs refused to lend their support, provoking outrage. At this time, Millwall had already moved away from the Isle of Dogs and had been playing in New Cross for 16 years.