Speaking as he unveiled 20 policies to outflank Mr Corbyn on the left, the MP for Pontypridd warned the UK was “more fractured and fragmented than ever before”.
In a speech at Orgreave in South Yorkshire, the site of a major flashpoint in the miners’ strike in 1984, he vowed to end austerity and lead a “socialist revolution” with a new “inequality-busting” wealth tax on the rich to pay for a 4 per cent increase in NHS spending.
In separate comments, Mr Smith said he was “really worried” about a possible split in the Labour Party, if Mr Corbyn retains the leadership against the wishes of four-fifths of Labour MPs.
Smith said: “What the form of that split looks like is unclear to me but there will obviously be some people in Wales and in Scotland who will think that you split along national lines. And I just think it’s a complete catastrophe for Labour if that were to happen.”
He added that pro-Corbyn figures such as shadow chancellor John McDonnell saw the Labour Party as “a vehicle for a revolutionary politics that he’s always espoused” and would be happy to see it split.
Mr Smith said he wanted to be the first Welsh prime minister since David Lloyd George, and dismissed claims that increasing devolution would mean no UK leader would ever again come from Scotland or Wales.
He said: “I’ve been really disappointed by some people who’ve said, ‘That’s not possible – in this sort of post-devolution era it can’t happen.’ Well, I completely reject that.
“I think it’s even more important in a post-devolution era that you’ve got people who come from outside London, outside England and have got a wider sense of the rest of the UK.”
In his speech yesterday, Mr Smith said he would appoint a Cabinet-level minister to deliver fair employment, end the public sector pay freeze and outlaw zero-hours contracts. He pledged to reintroduce the 50p top rate of income tax and reverse cuts to inheritance and capital gains taxes.
Under his plans, those with a taxable income of £150,000 per year or more would pay a levy of 15 per cent on “unearned income from investment”, raising £3 billion per year.
Other proposals from the former shadow work and pensions secretary include wage councils for hotel, shop and care workers, and an equal pay act that would end discrimination against women.
Mr Smith said Cabinet discussions under Mr Corbyn have been “devoid” of policy discussion, adding that he wanted Labour to take on Theresa May and “smash her onto her heels” – though he later apologised for the phrase.