Nigel Farage will be accused of wanting to "take Britain backwards" by vowing to scrap trade agreements between the UK and EU, as the government seeks a permanent deal to cut checks on food and drink.
The Reform leader wants to ditch the prime minister's Brexit reset package, unveiled earlier this year, which covers areas including fishing, defence, a youth experience scheme, and passport e-gates.
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It also includes a temporary deal to reduce the red tape on imports and exports of some fruit and veg, meaning no border checks or fees are paid - and the government wants to make it permanent when it expires in 2027.
The minister tasked by Sir Keir Starmer with improving UK-EU ties is Nick Thomas-Symonds, who will use a speech later today to say Mr Farage "wants Britain to fail".
Writing in The Telegraph in May, the arch-Brexiteer said Labour's deal takes the UK "back into the orbit of Brussels", and vowed a Reform government "would undo all of this legislation".
Speaking in central London, Mr Thomas-Symonds will say undoing it would slash "at least £9bn from the economy, bringing with it a risk to jobs and a risk of food prices going up".
The Cabinet Office minister will accuse him of offering "easy answers, dividing communities and stoking anger".
A Reform UK spokesperson has dismissed the incoming criticism, claiming "no one has done more damage to British businesses than this Labour government", pointing to tax rises on firms and the unemployment rate.
Nick Thomas-Symonds is on Sky News Breakfast - watch live from 7.15am.
'Farage's Brexit caused the small boats'
The Labour minister's criticism will come a day after Mr Farage revealed his controversial plans to stop small boat crossings, vowing any such arrivals - including women and children - would be detained and deported.
"If we do that, the boats will stop coming within days, because there will be no incentive to pay a trafficker to get into this country," he told a news conference on Tuesday.
Reform would repeal the Human Rights Act and leave the European Convention on Human Rights (ECHR), saying they have allowed foreign offenders to challenge their own deportations through the courts and remain in the UK.
Mr Farage said such treaties are "outdated", and that the British public were in a state of either "despair" or "anger" about illegal immigration.
Labour dismissed the proposals as "unworkable", while the Tories said he'd stolen their ideas.
Liberal Democrat leader Sir Ed Davey was more personal, suggesting Mr Farage himself was responsible for the massive rise in small boat crossings.
"The truth is, it was Farage's Brexit that caused the small boats," Sir Ed said. "Before Brexit, we could send back any illegal immigrants coming over in a small boat."
Read more:
Why Farage's small boats plan is not really about policy
How Farage's new 'leave' campaign could work and impact you
Did Brexit make things harder?
Brexit ended UK participation in the so-called Dublin agreement which governs EU-wide asylum claims. It means people should be processed for asylum in the country at which they first entered the bloc.
Sky News previously revealed how former immigration minister Chris Philp, now shadow home secretary, admitted it made returning illegal immigrants harder.
But Britain's membership of the EU did not stop all asylum arrivals. And many EU countries where people first arrive, including Italy, do not apply the Dublin rules.
Sir Ed said the government was now reduced to doing individual deals with countries to tackle the issue.
Labour are banking on a one in, out deal with the French, which will see the UK send asylum seekers to France in exchange for ones with links to the UK.
(c) Sky News 2025: Farage accused of wanting to 'take UK backwards' - as Brexit blamed for small boats crisis