Cabinet ministers allegedly told the BBC that plans are under discussion to kickstart economy with spending boost

The Government may raise capital spending on infrastructure as part of plans to inject £5bn into the economy without abandoning its deficit reduction strategy.

Cabinet ministers are said to have told BBC political editor Nick Robinson that discussions are underway about what can be done to boost sluggish growth without the need to resort to a fiscal Plan B.

But Lib Dems in Government distanced themselves from the suggestion of a £5bn plan.

Chief Secretary to the Treasury Danny Alexander told BBC Radio 4’s Today programme: “We’ve set out our policies on capital spending. We are going to stick to those policies across the board.”

Energy Secretary Chris Huhne said: “I don’t recognise that figure at all and I have absolutely no knowledge of that.”

Robinson said some ministers have suggested that road, rail and broadband projects could benefit from as much as £5bn in extra capital spending - on top of that committed in the March Budget.

The hint follows a speech by Nick Clegg last week, in which the deputy prime minister pledged to start “ramping up our sales pitch” in a bid to secure funding for infrastructure.

As leader of the Lib Dems, Clegg will speak at the party’s autumn conference tomorrow. His speech is expected to be dominated by Britain’s ongoing economic trials.