Rachel Reeves was accused on Wednesday of spelling 'disaster for business' by leaving her Budget until November 26.
The Chancellor was warned the decision to hold the event so late in the year threatened to create months of damaging speculation about tax rises and will stunt growth.
A report from Barclays said more than half of firms are delaying investment decisions until she reveals her plans.
The wait could also prove 'unnerving' for savers and put off prospective home buyers, experts claimed.
Meanwhile investors – said to be 'baying for spending cuts' as they sell off UK bonds and the pound – may also become frustrated at the delay in action to address Britain's parlous public finances.
