Scottish Labour Leadership candidate Jim Murphy is calling for all income tax to be devolved.
The former Scottish Secretary says the move would leave “no hiding place for those who want to talk about radical politics but then fail to deliver them.”
Murphy, who's the MP for East Renfrewshire, made the announcement during a speech in Glasgow earlier.
It would mark a change of policy for the party, but he says that's needed after years of failing to listen to the people:
“It is a clear signal to Scotland that we have changed, that we get it, that we will stand up for Scotland. On this central issue, we have listened to the people of Scotland and it is clearly an outcome that commands their support."
Mr Murphy is standing against MSPs Sarah Boyack and Neil Findlay in the contest for the party leadership, which was sparked by the resignation of Johann Lamont last month.
Ms Boyack, who was a minister under both Donald Dewar and Henry McLeish, has said she has reservations about devolving income tax, and would prefer to wait and see what is recommended by the Smith Commission.
The panel led by Lord Smith of Kelvin has been examining what, if any, new powers the Scottish Parliament should be given, and is expected to publish its report on Thursday,
Mr Findlay said the idea of fully devolving income tax has been around 'for years' and fetaured in a book to which he contributed - but he stopped short of giving a definitive position on the idea.
Voting began last Monday in the Labour leadership election and the results will be announced on 13th December.
Members are also electing a new deputy leader to replace Anas Sarwar. MP Katy Clark and MSP Kezia Dugdale are both in the running for that position.