The Doctor's first adventures were with his granddaughter Susan and her teachers, Ian and Barbara. Many companions followed, including Polly and Ben.

Some companions spanned several Doctors, among them the Brigadier (with moustache) and plucky journalist Sarah Jane Smith who later had her own series.

Like the Doctor, Romana was a Time Lord and could regenerate, thus being played by two actresses (Mary Tamm and Lalla Ward). Also seen is faithful robot dog K9.

Tegan (second right) entered the Tardis, thinking it was a real police box. She saw the fourth Doctor regenerate and travelled with the fifth.

Rose (L) was the 9th and 10th Doctors' companion and their relationship was exceptionally close. After Rose came Donna (C) and Martha.

Amy joined the 11th Doctor and explored relationships across time. The latest companion is Clara who has met the Doctor in previous incarnations.