Possibly a lad new in England, formerly (7)
I believe the answer is:
danelaw
'england formerly' is the definition.
I can't tell whether this definition defines the answer.
'possibly a lad new' is the wordplay.
'possibly' indicates an anagram.
'a'+'lad'+'new'='aladnew'
'aladnew' with letters rearranged gives 'DANELAW'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for danelaw that I've seen before include "Area of England settled by Vikings" , "NE England, once" , "Northern part of England when under foreign rule" , "old north" , "Part of country once" .)