1972–73, the club joined the newly formed Division Two of the Isthmian League. They won the division in 1975–76 and were promoted to Division One, which was renamed the Premier Division in 1977. In 1977–78 the club reached the FA Cup first round again; after defeating Kettering Town 3–2 in a second replay (the first match was declared null and void as Tilbury had used an ineligible player), they went on to beat Nuneaton Borough 2–1 in the second round, before being drawn away to Second Division Stoke City in the third round, a match they lost 4–0. In 1979–80 Tilbury finished bottom of the Isthmian League's Premier Division and were relegated to Division One. At the end of the 1986–87 season they were relegated to Division Two North, where they played until being transferred to Division Three in 1991 as a result of league reorganisation. The 1991–92 season saw the club finish third in Division Three, earning promotion to Division Two. Although they were relegated back to Division Three at the end of the 1997–98 season, another third-place finish in 1999–2000 saw the club promoted to Division Two again. League reorganisation led to the club being moved in to Division One North in 2002. They were subsequently transferred to Division One East of the Southern League for the 2004–05 season, in which they finished bottom of the table, resulting in relegation to the Essex Senior League. Tilbury finished third in their first season in the Essex Senior League and were promoted back to Division One North of the Isthmian League. A third-place finish in Division One North in 2011–12 saw them qualify for the promotion play-offs, in which they lost 4–3 to Needham Market in the semi-finals. Ground The club played on several different grounds in their early years, including the Green & Siley Weir ground, Daisy Field and at Tilbury Fort, before returning to the Green & Siley Weir ground in 1900. After World War I they moved to the Orient Field, a ground owned by one of the directors of Clapton Orient. During World War II the ground was commandeered by the Army for anti-aircraft guns being used to protect the docks. After the war, the club were told that they could only return to the Orient Field if they agreed to become a feeder club for Orient. After refusing, the club moved to an adjacent site