Jehoshaphat

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Jehoshaphat (also spelled Jehosophat and Jehosaphat) was an exclamation frequently uttered by the Third Doctor, sometimes prefixed with "jumping".

The Second Doctor exclaimed "Jumping Jehoshaphat!" when he saw that his new TARDIS had a working chameleon circuit. (PROSE: World Game)

After the Master escaped from prison, the Doctor exclaimed "Great jumping Jehoshaphat" when he realised that he was heading for Devil's End. (PROSE: The Eight Doctors)

The Doctor exclaimed "Jehoshaphat!" when he saw the carnage wrought by robot sheep. (PROSE: Verdigris)

In 1916 Russia, the Doctor exclaimed "Jumping Jehoshaphat!" when he saw that Vladimir Purishkevich and Ivan Sukhotin had thrown Grigori Rasputin into the Neva River. (PROSE: The Wages of Sin)

In the Death Zone, the Doctor exclaimed "Jehoshaphat!" upon recognising the Tremas Master. (TV: The Five Doctors)

On Dust, the Doctor muttered "Jehoshaphat" when he realised that his first incarnation had been brought to 76 Totter's Lane because it was actually I.M. Foreman's Travelling Show. (PROSE: Interference - Book Two)

In Mesopotamia, the Seventh Doctor summoned his third incarnation's personality to defuse Ishtar's cobalt bomb. The Doctor exclaimed "Jumping Jehoshaphat!" upon seeing how his seventh self was dressed. He said it again when he found that Ishtar was no longer in the TARDIS' telepathic circuits. (PROSE: Timewyrm: Genesys)

In Victorian London, Henry Gordon Jago exclaimed "Great jumping Jehoshaphat!" when he encountered a giant spider. (TV: The Talons of Weng-Chiang)

Some fans have theorised, not always entirely seriously, that Jehoshaphat is the Master's real name, based on the Doctor's line in The Five Doctors.