John McDonnell has defended his U-turn over Labour's economic policy, insisting he changed his mind about supporting George Osborne's plans after meeting families affected by the closure of the Redcar steelworks.
The shadow chancellor said he had "changed my mind on the parliamentary tactics" having originally said he would back Mr Osborne's plans for the Government to run a budget surplus.
Mr McDonnell said he viewed the updated Charter of Budget Responsibility as "meaningless" and had intended to "ridicule" it in the debate on Wednesday, but still vote in favour of it.
But explaining the U-turn, which has exposed bitter divisions within the Parliamentary Labour Party about the approach taken by Mr McDonnell and Labour leader Jeremy Corbyn, the shadow chancellor said he no longer wanted to be associated with Mr Osborne's policy.
Although Labour will now vote against the measure, Mr McDonnell insisted "we are not deficit deniers".
He told Sky News: "I haven't changed my mind on that, but I have changed my mind on the parliamentary tactics.
"Originally what I said to people was 'this charter is a political stunt, it is a political trap by George Osborne, it is virtually meaningless, he ignores it himself time and time again, he never meets his targets, so this is just a stunt, let's ridicule it in the debate and vote for it because it's a meaningless vote'."
Explaining his change of stance, which was ridiculed as a "total f****** shambles" following a fractious meeting of the Parliamentary Labour Party, Mr McDonnell said he had been struck by the potential impact of further austerity.
He said: "I went to Redcar and I met the steelworkers and I had families in tears about what's happened to them as a result of the Government failing to act, failing to intervene.
"I came back and I realised, as the consequences of Government's failure to invest in infrastructure, in skills, the cuts that are going to start coming now, I realised that people actually are going to suffer badly.
"It brought it home to me and I don't want the Labour Party associated with this policy."