His NHS practice is Whipps Cross University Hospital, London and his main private practices are at Holly House Hospital and Clementine Churchill Hospital, London. Dr Tahir specialises in autoimmune rheumatic disorders and is a Principal Investigator for clinical trials investigating new biological treatments for rheumatoid arthritis, psoriatic arthritis and Systemic Lupus Erythematosus; he also has an academic interest in all areas of sports medicine.