Despite the Prime Minister already ruling out remaining members of the single market, the Labour Party leader insisted leaving it would threaten jobs in the UK.
He raised the prospect of a Parliamentary rebellion as Mrs May prepares to trigger Article 50 on Wednesday and commence the two-year Brexit negotiation period.
Mr Corbyn told ITV’s Peston on Sunday: “We’re very clear that there has to be unfettered access to the European market, otherwise the threat to jobs in this country is absolutely huge.
“Most of our manufacturing industries have a European sale and European supply chain in them. And if we don’t maintain this unfettered access to the European market then quite clearly those industries are very much at risk.”
Jeremy Corbyn called for “unfettered access” to the single market
We’re very clear that there has to be unfettered access to the European market, otherwise the threat to jobs in this country is absolutely huge
He was then asked if he was “basically committing Labour to voting against Brexit” after it was pointed out to him that European leaders had ruled out access to the single market for post-Brexit Britain.
But Mr Corbyn said: “No we’re not… we’re not at the position of knowing what the deal is yet.”
The UK could leave the European bloc with a deal if Labour and enough Tory rebels voted against any proposed deal Mrs May presents to Parliament at the end of the negotiation period.
Tory MP Philip Davies hit out in response to the Labour leader’s comments. He told The Telegraph: "He may be trying sabotage but it would be futile sabotage as we are either leaving with a deal or leaving without a deal.
Jeremy Corbyn in pictures Tue, July 12, 2016
Labour Leader Jeremy Corbyn takes part in a community meeting at the Guru Har Rai Gurdwara Sahib temple
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Britain's opposition Labour Party leader Jeremy Corbyn speaks at an anti-racism rally in London
Theresa May is set to start Brexit negotiations this week
“If he wants to leave without a deal then clearly he would be voting for the hardest possible Brexit. Is that what he is advocating?”
Mr Corbyn also bashed Theresa May for wanting to bring in “Henry VIII” powers to amend primary legislation – Government bills – using secondary legislation, which are orders that go through Parliament with limited scrutiny.
While making the case for opposing the Great Repeal Bill, he said: “I don’t think the record of Henry VIII promoting democracy and inclusion and participation was a very good one.
“We need total accountability at every stage of this whole Brexit negotiation.
“We’re not going to sit there and hand over powers to this government to override parliament, override democracy and just set out a series of diktats. We’d be failing in our duty as democratically elected parliamentarians.”