Labour’s proposal to bring services such as water, energy and rail into public ownership would be “cost free”, John McDonnell has said.
The shadow chancellor says he wants to put public services “irreversibly in the hands of workers” so they can “never again be taken away”.
In a speech in London, Mr McDonnell said privatisation had failed.
However, the Conservatives said his plan would cost taxpayers billions of pounds and lead to worse services.
Earlier, Mr McDonnell told BBC Radio 4’s Today programme taking services into public ownership would not ultimately increase the burden on taxpayers because government bonds could be swapped for shares in a revenue-producing company.
“It would be cost free. You borrow to buy an asset and when that asset is producing profits like the water industry does, that will cover your borrowing cost,” he said.