Conversation so far:
What is the Shadow Chancellor of the Exchequer in the British Parliamentary system?
The Shadow Chancellor of the Exchequer in the British Parliamentary system is the member of the Shadow Cabinet who is responsible for shadowing the Chancellor of the Exchequer.
What did George Osborne do as Shadow Chief Secretary?
As Shadow Chief Secretary to the Treasury, George Osborne acted as the primary opposition to the Chief Secretary to the Treasury, who is deputy to the Chancellor of the Exchequer.
Did George Osborne's flat tax idea gain traction?
The idea of a flat tax was not included in the 2010 Conservative Party manifesto.
Was George Osborne's flat tax idea opposed?
The idea of a flat tax was not included in the 2010 Conservative Party manifesto.
Why wasn't George Osborne's flat tax idea included in the manifesto?
The Treasury has publicly rejected the flat tax idea as expensive and unfair.
What other policies did George Osborne look to implement besides the Flat tax idea?
George Osborne launched the Northern Powerhouse initiative.

Question: Can you tell me a bit more about the time period that he was Shadow Chancellor? What else of note did he do?
Self-contained rewrite: Can you tell me a bit more about the time period that George Osborne was Sahdow Chancellor? What else of note did he do?