St . George ’ s Hospital is the largest hospital in the United Kingdom , primarily serving 1.3mn people in southwest London and significant populations of Surrey and Sussex , totalling around 3.5mn . The hospital itself is 200 years old and is one of country ’ s principle teaching and training hospitals . St George ’ s has 1,300 beds and around 8,500 staff members as well as having several centres of excellence , such as its stroke care and cardiology unit . It was merged with community services Wandsworth in 2010 to integrate the provision of healthcare in the area .