UPDATE: 3.30pm BST

A spokesman for Smith said: "It was off script and on reflection it was an inappropriate choice of phrase and he apologises for using it."

Labour leadership challenger Owen Smith risked allegations of sexism after he declared that his party should "smash" Theresa May "back on her heels" during prime minister's questions. The Pontypridd MP made the comments during a major speech in Orgreave, South Yorkshire, on Wednesday morning (27 July).

But Smith, 46, defended his language when pressed by journalists. He stressed that the remarks were "rhetoric" and said Labour should be standing up for people. "I don't literally want to smash Theresa May back. I'm not advocating violence in any shape or form," he stressed.

The former shadow work and pensions secretary unveiled a range of policies, including a pledge to introduce a 50p tax rate, reverse cuts to inheritance tax and ban zero-hours contracts.

Workers' rights were at the heart of Smith's speech, with another commitment to bring back wage councils, which were scrapped under Margaret Thatcher.

The left-wing policies indicate Smith is attempting to win over some of Jeremy Corbyn's supporters, after the Islington North MP won almost 60% of the vote in Labour's 2015 leadership election.

Key dates of the Labour leadership election

  • 18 July: Signing up as a registered supporter to vote in the election begins.
  • 19 - 20 July: Number of MP nominations for each candidate to be published.
  • 20 July: Deadline for people to sign up as a registered supporter closes.
  • 22 August: Ballot papers will begin to be sent out around the UK, but to Labour Party members only.
  • 21 September: Deadline for ballot papers to be returned is midday.
  • 24 September: The election result will be announced at a Leadership Conference in Liverpool.

"We welcome Owen's focus on equality of outcome, reindustrialisation and workers' rights – and his support for policies announced in recent months by Jeremy Corbyn and John McDonnell," a spokesperson for the Jeremy for Labour campaign said.

"We are delighted that he has echoed John McDonnell's call for the reinstatement of a Ministry of Labour, made last month at the Institute of Employment Rights (28/6/16), and Jeremy Corbyn's call for a ban on exclusive workforce recruitment from abroad, made during the referendum campaign, among other policies.

"Owen's speech today shows the leadership that Jeremy Corbyn has demonstrated in placing economic justice and fairness back at the heart of Labour politics. Under Jeremy, Labour has put restoring dignity and pride in our communities worst hit by decades of neglect at the core of our politics."

The 20 policies announced by Owen Smith

  • A pledge to focus on equality of outcome, not equality of opportunity.
  • Scrapping the DWP and replacing it with a Ministry for Labour and a Department for Social Security.
  • Introducing modern wages councils for hotel, shop and care workers to strengthen terms and conditions.
  • Banning zero hour contracts.
  • Ending the public sector pay freeze.
  • Extending the right to information and consultation to cover all workplaces with more than 50 employees.
  • Ensuring workers' representation on remuneration committees.
  • Repealing the Trade Union Act.
  • Increase spending on the NHS by 4% in real-terms in every year of the next parliament.
  • Commit to bringing NHS funding up to the European average within the first term of a Labour Government.
  • Greater spending on schools and libraries.
  • Re-instate the 50p top rate of income tax.
  • Reverse the reductions in Corporation Tax due to take place over the next four years.
  • Reverse cuts to Inheritance Tax announced in the Summer Budget.
  • Reverse cuts to Capital Gains Tax announced in the Summer Budget.
  • Introduce a new wealth Tax on the top 1% earners.
  • A British New Deal unveiling £200bn of investment over five years.
  • A commitment to invest tens of billions in the North of England, and to bring forward High Speed 3.
  • A pledge to build 300,000 homes in every year of the next parliament – 1.5 million over five years.
  • Ending the scandal of fuel poverty by investing in efficient energy.