The most common and most likely answer to this crossword clue is the 8 letter word AUTOCRAT
I've seen this crossword clue in The Daily Telegraph
A
U
T
O
C
R
A
T
More clues leading to the result AUTOCRAT
- Despot in car, an unreliable one, mostly
- Dictatorial boss of car firm?
- Cart crashing behind car, one with lots of power
- Big Brother writer has cast actor for second half
- Despot Hitler finally snatched by Jaguar, say?
- Despot in car, more or less despicable type
- Quite regularly visiting area, ordinary Balkan inhabitant having no love for dictator
- He favours dictation above all his subjects
- Tyrant in boozy party holding court, dancing with famous model
- His word is law at a court building
Buddy explains!

The straight part
We know that "Despot" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case despot = autocrat.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does AUTOCRAT mean?
AUTOCRAT noun- An absolute ruler with infinite power.
- A title borne by some such monarchs, as in Byzantium and tsarist Russia.