South Bank Polytechnic Student Union was formed in 1970 by amalgamating the unions of the Borough Polytechnic Institute, Brixton School of Building and City of Westminster College after these institutions were merged, along with the National College for Heating, Ventilating, Refrigeration and Fan Engineering to form the Polytechnic of the South Bank.
The Borough Polytechnic Students' Union had been situated in Borough Road Building, but the new South Bank Polytechnic Student Union was located on Rotary Street where facilities included a bar, coffee bar and games room. By 1973 the Union had established a Welfare Service and the clubs and societies on offer were categorised into four groups: sporting; academic; entertainments; and other. The Union promoted itself as "the only democratic organisation within the Polytechnic representing student's interest to the college and other authorities as a Union". As well as the building on Rotary Street, the Student Union also had a presence at Wandsworth Road Building, after its opening in 1973.
In 1987 the Polytechnic purchased the Vickers Building on Keyworth Street, which was renovated in order to house the finance department and the Student Union. Work was completed in 1990 and the building was renamed George Overend Building. It contained a Student Union shop and bar, a hairdressers and an events hall and was the second largest student venue in London. In 1993 the Union opened a shop in Wandsworth Road and in total provided four bars, two shops, a recreation room and student common room for the Polytechnic's students. The four categories for clubs and societies were altered to become: course based; cultural; external; and sports.
In January 1994 the Union opened a mini-mall on Keyworth Street containing the new Union shop, Endsleigh Insurance and a small space for amusement machines. The Union also expanded its welfare unit and opened two new entertainment venues within George Overend Building: The Void for smaller events and The Arc, which had space for 1,000 people. The venues within George Overend Building were refurbished and changed name several times, but by 1999 consisted of the Tavern, a bar styled as a traditional pub and Isobar, a larger venue.
The Student Union ceased to have facilities at Wandsworth Road in 2003 once the building was sold. It also ceded management of Turney Road Sports Pavilion to the University's Academy of Sport, Physical Activity & Wellbeing in 2006.
In 2007 the Student Union was relocated to a temporary structure on Thomas Doyle Street in order for the George Overend Building to be demolished. The temporary structure contained a shop, bar events area, outdoor seating and offices. The Union remained here until November 2012 when it moved to the newly built Student Centre next to Borough Road Building.