Labour backbencher John McDonnell urged ministers to review the possibility of incorporating a bank financial transaction tax within the bank levy.

BBC: Finance (No.3) Bill

But John McDonnell said that wasn't good enough - for him, there had to be "absolute solidarity" - "no ifs no buts".

BBC: Labour conference: Left frustrated by 'Red Ed'

Labour MP John McDonnell has presented a private members bill to make it possible, but without government support it is unlikely to succeed.

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