The most common and most likely answer to this crossword clue is the 7 letter word NEWGATE
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More clues leading to the result NEWGATE
- Invalidate housing with old prison
- Deny wife is held in old prison
- Old prison has modern entrance
- Old prison of Great Wen put up, then demolished
- One taking the place of an old swinger in prison long ago
- Deny grabbing women from a London street
- Fresh group of spectators in a stir once
- Deny going round women’s prison
- Old can opener beyond contemporary
- Fresh entrance for old prison
Buddy explains!

The straight part
We know that "old prison" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old prison = newgate.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.