PRIME Minister Sir Keir Starmer is struggling to keep the lid on a mounting rebellion among backbench Labour MPs over his planned attack on welfare.

Dozens of MPs are not buying his argument that massive cuts are justified because the welfare system is “unsustainable, indefensible and unfair.”

The PM is targeting benefits for disabled people in particular, with Welfare Secretary Liz Kendall expected to outline plans for spending reductions next week.