Sept 22 (Reuters) - Activist investor Bluebell Capital Partners has taken a small stake in British pharmaceuticals group GlaxoSmithKline in efforts to shake up top management, a Financial Times report here said on Wednesday. In a letter sent to GSK’s chairman Jonathan Symonds, Bluebell called for chief executive Emma Walmsley to reapply for her job as she would have “renewed credibility both internally and externally”, the FT report said. Earlier this year, activist Elliott had also taken a stake in GSK, calling for a leadership change at the company. (Reporting by Aditi Sebastian in Bengaluru. Editing by Jane Merriman)