Old PM happy one around street (9)

I believe the answer is:

gladstone

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'old pm' is the definition.
'gladstone' can be an answer for 'pm' (Victorian UK prime minister William Gladstone). I am unsure of the 'old' bit.

'happy one around street' is the wordplay.
'happy' becomes 'glad' (similar in meaning).
'around' means one lot of letters goes inside another.
'street' becomes 'st' (abbreviation).
'glad'+'one'='gladone'
'gladone' going around 'st' is 'GLADSTONE'.

Can you help me to learn more?

(Other definitions for gladstone that I've seen before include "C. nineteenth Liberal prime minister" , "Victorian GOM" , "5,27 [PRIME MINISTER]" , "So tangled up with old British Prime Minister" , "Former English PM or kind of bag" .)

I've seen this clue in The Sun.

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