Danny Alexander has said no-one should face a cut in state help if no suitable smaller property is available and all disabled claimants should be exempt.
In a direct message to the Conservative government, the Chief Secretary to the Treasury said the Liberal Democrats will "make the case for these new fairer rules."
Speaking to The Mirror he said: "If we can't convince our Conservative coalition partners, we will commit to these reforms in our 2015 manifesto."
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The child’s mother, who is in her late twenties, along with two men in their late teens, were also taken to hospital.
'Car Crime: Is My Car Safe?' with reporter Alex Beresford is on ITV tonight at 7:30pm.
Government is expected to spend £132.5 billion on coronavirus policy interventions, up 7.5% on previous estimates last month.