Rachel Reeves hit out at 'unproven' wealth taxes today amid fresh Labour demands to soak the rich.
The Chancellor insisted there is no certainty about what revenue a new levy would bring in as she was confronted by an MP in the Commons.
Ms Reeves is under huge pressure to find a way of balancing the books as the Budget looms on November 26.
There have been warnings that the gap in the public finances could be as big as £50billion amid the slowing economy, rising debt interest costs and calls for more spending.
Businesses have been increasingly voicing alarm about the impact of Labour's policies, including the national insurance hike and employment rights' overhaul.
