The most common and most likely answer to this crossword clue is the 7 letter word TUMBREL
I've seen this crossword clue in The Daily Telegraph
T
U
M
B
R
E
L
More clues leading to the result TUMBREL
- Farm cart new butler observed across motorway
- Glass changing hands in this checkout cart
- Organ originally borne on large farm cart
- Leaving hospital, hitch lift on large revolutionary cart
- Acrobat ends with somersault into wagon
- Last three bits of glass thrown back in cart
- Vehicle submerged in a sea of lost umbrellas
- Met Blur, excitedly — many were carried away by it and lost their heads
- Cart in which acrobat swaps sides
- Acrobat switching directions to make cart
Buddy explains!

The straight part
We know that "many were carried away by it and lost their heads" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case many were carried away by it and lost their heads = tumbrel.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 TUMBREL mean?
TUMBREL noun- A kind of medieval torture device, later associated with a cucking stool.
- A cart which opens at the back to release its load.
- A cart used to carry condemned prisoners to their death, especially to the guillotine during the French Revolution.
- A basket or cage of osiers, willows, or the like, to hold hay and other food for sheep.