The most common and most likely answer to this crossword clue is the 7 letter word STEPHEN
I've seen this crossword clue in The Daily Telegraph
S
T
E
P
H
E
N
More clues leading to the result STEPHEN
- Martyr succeeded after that, retaining record
- St Wenceslas’s feast day?
- Boy makes move in dance with girl
- King who has feast after Christmas?
- Old king has put foot down over broody female
- Fry, say, chicken after favourite starter of salmon’s revolting
- Man remembered on Boxing Day taking walk with female
- Man to walk ahead of gossipy female
- Guinea pigs possibly climb over bird ruler
- He gets a bird on flight
Buddy explains!

The straight part
We know that "Man remembered on Boxing Day" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case man remembered on boxing day = stephen.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.