15 Best Companions In Doctor Who History
4. Sarah Jane Smith (Elisabeth Sladen)

Widely regarded as the ultimate Doctor Who companion, journalist Sarah Jane travelled with the Third and Fourth Doctors and first appeared in The Time Warrior.
She built up a close rapport with the Doctor and saw him move away from his association with UNIT. Sarah Jane was pretty fearless, though there were times she had to be pulled out of a sticky situation. Her last story in her original run was The Hand of Fear but, as you'll know, she came back several times.
She had two series of her own, K-9 & Friends and The Sarah Jane Adventures, and made countless appearances in later episodes of Doctor Who, including the modern era. The Sarah Jane Adventures only ended, much to the heartbreak of her new generation of fans and older ones alike, with the unexpected death of actress Elisabeth Sladen in 2011.