Chancellor Philip Hammond said Brexit was creating "very significant" uncertainty about the economic outlook, deterring business investment and limiting his ability to make long-term plans on spending and taxes.
Hammond said the government was on track to meet its future fiscal targets and there was significant headroom in his budget for flexibility on spending or tax decisions, but Brexit was stalling longer-term planning.
"Given that there is very significant uncertainty about the future trajectory of the economy right now, and will remain so until we have resolved the Brexit issue, I don't think it makes sense to plump for one option or another," he told.