Ms Curran’s strong signal that Labour could be willing to cut a deal on one of the major points of contention over the future of more powers for Scotland came as the starting gun was fired on legislation for new powers with the publication of a command paper by the UK government.
The admission by Ms Curran came amid private concerns by Scottish Labour MPs – fearful of losing their seats to the SNP – that the party could be left looking “anti-devolution” because it is the only one against handing over all of income tax.
One senior Labour backbencher told The Scotsman that “it would be suicidal” not to compromise.
Mr Brown has described full devolution of income tax as “a Tory trap” because of the Conservative push for English votes for English laws which would prevent Scottish MPs voting on key parts of the Budget.
But Ms Curran said: “When Gordon Brown puts in an argument about Tory traps that is compelling and we need to hear that.”
But she added: “I am going into the Smith Commission open minded about the arguments. We want to be constructive in our approach with this.”
Labour’s devolution commission recommended handing over 15p of the 20p basic rate.
Ms Curran said: “If someone comes to me and says actually there are some arguments you have got wrong and this might not under cut Scottish resources I would listen to that.”
She said the party’s “key two tests” of the conclusions of the commission chaired by Lord Smith of Kelvin are that they properly respect the referendum result and work best for the people of Scotland.
She said this means “pooling resources across the whole of the UK.”
In his statement to parliament, Scottish Secretary Alistair Carmichael insisted the timetable would not slip and legislative proposals would be in place by Burns Night – 25 January.
He also warned Nationalists that it would “not be independence by the back door.”
But SNP Perth MP Pete Wishart claimed that “two thirds of Scottish voters want devo-max” including the devolution of taxation.
Mr Carmichael faces pressure from English Tories to introduce English votes for English laws alongside more powers for Scotland.
Tory MP Crispin Blunt said: “You don’t have a mandate for more powers for Scotland without English votes for English laws.”