The most common and most likely answer to this crossword clue is the 1 letter word T
I've seen this crossword clue in The Times
T
More clues leading to the result T
- Perhaps carpet worker’s collective has the right answer
- Halt, a jam involving Marble Arch in a big way
- always does contrive – Fal lal la!
- Korean city rejected enormous capital cover without any hospital
- Cap on India’s prime cultivated land united one of its states
- Tempe’s vale next ancient Peneus came,
- Messos’ blue-eyed nymphs delight to rove,
- - BENT [with crook] + HAM [bad actor]. Jeremy Bentham the utilitarian and ongoing resident of a cupboard in UCL.
- what a beautiful clue! Just put TTAGinside AIR, then add L.
- Clark Kent with moustache, of course.
Buddy explains!

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.