Diane Abbott and other backbenchers refuse to join leadership in backing Osborne's measure.
Shadow defence secretary Vernon Coaker should outline a vision for modern left multilateralism.
The Budget has revealed how vulnerable Labour is to the charge that it doesn't really trust voters to manage their affairs.
Osborne's populist Budget helps the Conservatives claw back voters from UKIP.
The Labour leader uses the Scottish First Minister's weapon of choice against him.
For the sake of a day of good headlines and a few billion pounds of extra tax, the Chancellor has put years of painful progress at risk.
Voters will still be worse off in 2015 than in 2010 - Labour's "cost-of-living" strategy remains its best hope of victory.
Party's decision could lead to backbench rebellion.
"This is the Budget that confirms people are worse off under the Tories."