Jeremy Corbyn will set out Labour’s “good Brexit plan” on Monday, saying that leaving the European Union must be the catalyst for a “radical programme of investment and real change” as the party steps up efforts to show it has an alternative to Theresa May’s approach.

Speaking to business leaders at the CBI’s annual conference in London, which will also be addressed by the prime minister, Corbyn will claim May’s deal, published last week, would “leave the country in an indefinite halfway house without a real say over our future”.

Instead, he will say, “a good Brexit plan for this country is not just about what can be negotiated with Brussels. It must also include a radical programme of investment and real change across our regions and nations.

“Brexit should be the catalyst to invest in our regions and infrastructure, bringing good jobs and real control to local communities and people.”

His words are likely to infuriate those Labour MPs who believe the party’s stance should be to seek to block Brexit by pressing for a referendum on May’s deal – with the option of remaining in the EU on the ballot paper.

Corbyn played down that suggestion on Sunday, telling Sky News’ Sophy Ridge: “It’s an option for the future, but it’s not an option for today. If there was a referendum tomorrow, what’s it going to be on, what’s the question going to be?”

Asked how he might vote in such a referendum, Corbyn said, “I don’t know how I am going to vote, what the options would be at that time.”

Play Video 1:24 'An option for the future': Corbyn on second Brexit referendum – video

In his speech to the CBI, Corbyn will set out the key elements of what he will call Labour’s “sensible” approach.

Instead of the temporary customs arrangement May has signed up to as a backstop, to prevent a hard border in Ireland, Corbyn will underline Labour’s backing for a permanent customs union.

He will stress the need for workers’ rights and environmental standards to be protected to prevent a “race to the bottom”.

And he will call for “a strong single market relationship that allows British business continued access to European markets for both goods and services – while also ensuring we have the powers to support our public services and industry and transform the economy in all our regions and nations.”

Labour believes it needs to have something to offer its supporters in heavily leave-voting seats, regarding their backing for Brexit not just as a rejection of unfettered immigration but as a demand for economic change.

When May brings her final deal back to parliament, expected to be early next month, Labour will whip its MPs to vote against it. Then, if the deal is rejected by parliament, the party will demand the opportunity to pursue its own alternative approach.

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“If the prime minister is unable to negotiate an agreement that can win a majority in parliament and work for the whole country, Labour’s alternative plan can and must take its place,” Corbyn will say on Monday.

But it is as yet unclear how Labour could secure enough support from MPs to push its own proposals.

The shadow Brexit secretary, Keir Starmer, will address Labour MPs at the regular meeting of the parliamentary Labour party on Monday night and urge MPs to hold their nerve in the face of the threat that rejecting May’s deal would result in a no-deal Brexit.

Corbyn, a longstanding critic of the EU, was asked by Ridge whether Labour was offering enough leadership over Brexit and whether it could play a bigger role in coordinating those opposed to the government’s withdrawal agreement.

He replied: “There was a referendum in 2016, a majority voted to leave the EU, there are many reasons why people voted. I don’t think you call a referendum and then say you don’t like the result and go away from it. You’ve got to understand why people voted and negotiate the best deal you can.”