Labour will “get Brexit sorted within six months” – and give the British public the final say, Jeremy Corbyn is set to declare in a major campaign speech on Tuesday.

On a visit to Harlow in Essex, a key target seat for Labour, the opposition leader is expected to spell out his position on Brexit and attack the Conservative Party’s vision for taking the UK out of the EU.

Corbyn will counter the Tory campaign slogan promise to “get Brexit done” with his own promise to resolve the issue – and he is set to attack Boris Johnson’s plan to “hijack Brexit to sell out our NHS and working people”.

Labour has been accused of lacking a clear line on Brexit, and of being ambiguous in its stance. The second major speech by Corbyn of the general election campaign is designed to combat such criticism.

“A Labour government will get Brexit sorted within six months by giving you, the British people, the final say,” the Labour leader will say on Tuesday morning. “It won’t be a re-run of 2016. This time the choice will be between leaving with a sensible deal or remaining in the European Union.

“An incoming Labour government will first secure a sensible deal. That will take no longer than three months because the deal will be based on terms we’ve already discussed with the EU, including a new customs union, a close single market relationship and guarantees of rights and protections.

“So if you want to leave the EU without trashing our economy or selling out our NHS you’ll be able to vote for it. If you want to remain in the EU, you’ll be able to vote for that.

“Either way, only a Labour government will put the final decision in your hands. And we will immediately carry out your decision so Britain can get beyond Brexit.”

On Tory plans for Brexit, Corbyn is expected to say: “Boris Johnson is trying to hijack Brexit to sell out our NHS and working people. Many people who voted to leave tell me they were voting for change. Johnson and the Leave campaign promised to rebuild our NHS.

“Johnson stood in front of a bus and promised £350m a week for the NHS. Now we find out that £500m a week could be taken out of the NHS and handed to big drugs companies under his plans for a sell-out trade deal with Donald Trump.

“We now know that US and UK officials have been discussing drug pricing in secret and the US government is demanding “full market access for US products.” Senior NHS managers have said that would mean “higher prices for medicines” which will “pass on costs to both patients and the NHS.”

“Behind the scenes, the Conservatives have tried to suppress the news, attacking the BBC for reporting what we and health professionals are saying. This is what they don’t want you to hear: a vote for Johnson’s Conservatives is a vote to betray our NHS in a sell-out to Trump.

“Johnson’s Trump deal Brexit puts a price tag on our NHS. So we’ll say it again and again until the message gets through to the White House: our NHS is not for sale.”

Keeping Brexit tightly linked to the Tory threat to the NHS and Labour’s intention to protect free healthcare at the point of use, Corbyn will say: “This threat to our NHS isn’t a mistake. It’s not happening by accident.

“The threat is there because Boris Johnson’s Conservatives want to hijack Brexit to sell out the NHS and sell out working people by stripping away their rights. Given the chance, they’ll run down our rights at work our entitlements to holidays, breaks and leave.

“Given the chance, they’ll slash food standards to US levels where “acceptable levels” of rat hairs in paprika and maggots in orange juice are allowed and they’ll put chlorinated chicken on our supermarket shelves.

“And given the chance, they’ll water down the rules on air pollution and our environment that keep us safe. They want a race to the bottom in standards and protections. They want to move us towards a more deregulated American model of how to run the economy.

“In the US, workers get just ten days holiday a year, big business gets free rein to call the shots and tens of millions are denied healthcare. What Boris Johnson’s Conservatives want is to hijack Brexit to unleash Thatcherism on steroids.

“Margaret Thatcher’s attack on the working people of our country left scars that have never healed and communities that have never recovered. The Conservatives know they can’t win support for what they’re planning to do in the name of Thatcherism. So they’re trying to do it under the banner of Brexit instead.”

Corbyn will be joined at the event by Labour’s Brexit shadow cabinet spokesperson Keir Starmer, rising star Laura Pidcock and Laura McAlpine, who grew up in Harlow and is considered by the leadership to be one of the party’s strongest candidates.

McAlpine has been picked to challenge Tory incumbent Robert Halfon, who has a majority of just over 7,000 votes. The bellwether seat is thought to be an important target for Labour at the upcoming election.