Labour Party leader Jeremy Corbyn | Leon Neal/Getty Images Jeremy Corbyn names his price for backing Brexit deal Labour leader tells Theresa May in his conference speech that if she cannot clinch a Brexit deal ‘you need to make way for a party that can and will.’

LIVERPOOL, England — Jeremy Corbyn made continued membership of the EU’s customs union his price for backing any final Brexit agreement struck by Theresa May, as he set out an alternative negotiating strategy at the party’s annual conference in Liverpool Wednesday.

In a speech lasting just under an hour, Corbyn called for party unity to force the Conservative Party from power, giving Labour the chance to finish the job of negotiating Britain’s exit from the EU. He branded the prospect of a no-deal Brexit a "national disaster."

In a strikingly conciliatory tone distancing the party from hard-line Remainers who are pushing for a second referendum with the option to remain in the EU, Corbyn said he wants to “reach out” to the prime minister to offer his support in the final vote on the terms of Britain’s Brexit divorce. But that support would only come if the deal keeps Britain inside the EU's customs union, while meeting a series of other demands on maintaining standards.

“Brexit is about the future of our country and our vital interests,” he told the packed auditorium in Liverpool. “I say this to her in all sincerity and helpfulness. If you deliver a deal that includes a customs union and no hard border in Ireland, if you protect jobs, people’s rights at work and environmental and consumer standards — then we will support that sensible deal. A deal that would be backed by most of businesses in world and trade unions.”

The offer is not new in substance — mirroring five of Labour’s long-trumpeted “six tests” — but is far more conciliatory in tone than the original demand that any Brexit deal must achieve “the exact same benefits” of both single market and customs union membership.

Corbyn said that if May could not negotiate continued customs union membership “you need to make way for a party that can and will.”

The Labour leader’s words will offer encouragement to many in Brussels who continue to hope that the U.K. will remain in a customs union with the EU, easing the Northern Irish border problem and cross-border supply lines between Britain and mainland Europe.

Corbyn’s speech was short on detailed policy, but high in rhetoric, promising to “rebuild Britain for the many not the few” with a radical overhaul of the economy.

He painted Labour as a party ready for power, “ready to take charge, rebuilding our divided country.”

“Change in our country is long overdue,” he told the crowd who broke into chants of “Oh Jeremy Corbyn” throughout the speech. “Every month this government remains in office, things get worse. After a decade of austerity a Labour government will confront the challenge of rebuilding our public services.”

Corbyn reannounced plans for more child care, new taxes on the wealthy and a complete overhaul of Britain’s foreign policy. “No more reckless wars of intervention like Iraq or Libya,” he declared. The loudest cheers were saved for his announcement that he will recognize a Palestinian state as soon as Labour takes office.