Labour wants a softer Brexit than Ms May’s withdrawal agreement proposes.
Its priorities include a customs union with the European Union (EU), access to the single market, and protections for consumer, environmental and workers’ rights.
“We’re also very clear that there has to be an absolute guarantee that the Good Friday Agreement is maintained for peace in Northern Ireland,” Mr Corbyn said.
Brexit billboards: Campaigners remind MPs of past promises
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In February, Mr Corbyn wrote to the prime minister pledging to throw his party's support being her Brexit deal if she agreed to five binding commitments.
Those were:
A “permanent and comprehensive UK-wide customs union”, including a say in future trade deals
Close alignment with the single market, underpinned by “shared institutions and obligations”
“Dynamic alignment on rights and protections”, so UK standards do not fall behind those of the EU
Clear commitments on UK participation in EU agencies and funding programmes
Unambiguous agreements on future security arrangements, such as use of the European arrest warrant and shared databases
Labour last year also outlined six “tests” by which it said it would judge the prime minister’s Brexit deal.
Keir Starmer, the shadow Brexit secretary, said his party would vote against any withdrawal agreement that did not meet those criteria – which included delivering the "exact same benefits" as being in the single market and customs union.
It remains to be seen if Labour is will to give ground on any of its priorities as seeks to avert a no-deal Brexit.
Ms May's own red lines include making sure the UK is out of the customs union, while she has also ruled out a second referendum - something Labour would back to confirm to terms of the withdrawal agreement.
But a Number 10 source said "unless there is compromise on both sides, it is unlikely we can find a way forward".
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