Keir Starmer will accuse the Tories of creating a "hulking fatberg" of Brexit red tape in a speech laying out Labour's plans for the future relationship with Brussels.
The Labour leader is expected to unveil his new plan to "Make Brexit Work", in a nod to Boris Johnson's election-winning promise to "Get Brexit Done" in 2019.
In a speech today, Mr Starmer will say Labour won't undo Brexit and make it clear he won't try to rejoin the EU's single market and customs union.
But he will denounce the "mess" created by Mr Johnson and say the Tories have "created a hulking ‘fatberg’ of red tape", in a comparison to the 'wet wipe island' found in the river Thames.
“It is hampering the flow of British business. We will break that barrier down," he was due to say, according remarks first trailed to the FT.
Mr Starmer, who was Shadow Brexit Secretary under Jeremy Corbyn, has been quiet on his former brief amid deep divisions in the party's ranks over the issue.
But he will underline his commitment to making Brexit work in an attempt to see off Tory accusations that Labour is lukewarm on the UK's departure from the EU.
Today, Mr Starmer will set out his five-point plan to "sort out the poor deal Boris Johnson signed, and end the Brexit divisions once and for all" in a speech to the Centre for European Reform.
Labour would fix the Northern Ireland protocol, which Mr Johnson is threatening to tear up, and tear down trade barriers with a new UK-wide veterinary agreement.
But he will vow not undo Brexit, saying: "We cannot afford to look back over our shoulder. Because all the time we are doing that we are missing what is ahead of us.
"So let me be very clear: with Labour, Britain will not go back into the EU. We will not be joining the single market. We will not be joining a customs union.
"The reason I say this is simple. Nothing about revisiting those rows will help stimulate growth or bring down food prices or help British business thrive in the modern world.
"It would simply be a recipe for more division, it would distract us from taking on the challenges facing people, and it would ensure Britain remained stuck for another decade."
It comes as Mr Starmer awaits the outcome of the Durham Police investigation into Beergate, which could come as early as this week.
He has tied the future of his leadership to whether he gets fined by the police for having a beer and a takeaway curry with activists ahead of the Hartlepool by-election in 2021.
Stella Creasy, chair of the Labour Movement for Europe, said: "This speech finally opens the door to a different future with Europe from the chaos Boris Johnson is creating.
"We are only just beginning to understand the damage Brexit is doing to Britain so we urge Keir to make sure nothing is off the table as a solution in the fight to tackle the cost of living crisis and protect jobs, trade and security."
But SNP Westminster leader Ian Blackford said: "The Labour Party are now indistinguishable from the Tories on Brexit. By running scared of the Tories and mutating into a pale imitation of Boris Johnson, Starmer is offering no real change at all.
"With all the Westminster parties ruling out a return to the EU, the single market and customs union, it is clear there is no route back to Europe and economic prosperity at Westminster.
"With this hard Brexit U-turn Keir Starmer has perfectly encapsulated why Scotland needs to escape from Westminster control."
