What law's Tom broken somewhere in London? (11)

I believe the answer is:

walthamstow

I'm a little stuck... Click here to teach me more about this clue!

'somewhere in london?' is the definition.
The definition suggests a singular noun which matches the answer.

'what law's tom broken' is the wordplay.
'broken' indicates anagramming the letters.
'what'+'laws'+'tom'='whatlawstom'
'whatlawstom' with letters rearranged gives 'WALTHAMSTOW'.

Can you help me to learn more?

(Other definitions for walthamstow that I've seen before include "Gtr London town" , "London area" .)

I've seen this clue in The Telegraph.

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