Buy saw forged underground across the pond (6)

I believe the answer is:

subway

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

'underground across the pond' is the definition.
I can't tell whether this defines the answer.

'buy saw forged' is the wordplay.
'forged' is an anagram indicator.
'buy'+'saw'='buysaw'
'buysaw' is an anagram of 'SUBWAY'.

Can you help me to learn more?

(Other definitions for subway that I've seen before include "US underground railway" , "Passage under a road" , "New York city trains" , "Underground rail" , "Pedestrian underpass" .)

I've seen this clue in The Independent.

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