The Conservatives say they would task officials with removing 750,000 illegal immigrants from the UK within five years if they win the next election.

Under plans unveiled as its annual conference begins, the party has pledged to ban people who enter the UK without permission from ever claiming asylum.

It would also prevent those whose claims are rejected from challenging decisions in the courts, with appeals instead handled by Home Office officials.

Border officials would be instructed to remove people “within hours or at most a few days”, the Tories say, with a reformed “Removals Force” unit seeing their funding doubled to £1.6bn per year.

It comes as Tory activists gather in Manchester for their annual party conference, amid dire poll ratings under leader Kemi Badenoch and questions over how they can head off a potentially existential challenge from Nigel Farage’s Reform UK.

In the run-up to the four-day gathering, the party has already said it would end the UK’s 75-year membership of the European Convention on Human Rights (ECHR) in a bid to thwart asylum appeals, confirming a widely-expected policy shift.

Under the latest proposals, the Home Office’s immigration enforcement unit would be rebranded as a “Removals Force” and given wider-ranging powers, along with an extra £820m per year the Tories say could be unlocked by closing asylum hotels.

The party says it would give the new unit a “mandate” to remove at least 150,000 people each year, totalling 750,000 during the five-year lifetime of a Parliament.

This would include people currently living in the UK illegally, the party says, as well as future illegal arrivals and all foreign nationals convicted of a crime more serious than minor parking or speeding offences.

It would represent around a five-fold increase from the 35,000 migrants who were removed from the UK over the last year – the majority of whom went voluntarily.

The party says it wanted to take inspiration from the US, where President Trump has handed immigration enforcement officers sweeping new powers to arrest and deport undocumented migrants.

The Tories say they would instruct police forces to check the details of everyone they arrest against biometric borders data, and would be allowed to use facial recognition without informing the public it is in use.

It plans to expand an unspecified “existing facility” to detain migrants before they are removed, with a capacity for between 1,000 and 2,000 people.

The party also plans to restrict the grounds for claiming asylum to those facing a threat from the government in their home country, excluding claims from those fleeing conflict or “less tolerant” laws on religion or sexuality.

Key to their proposals is a plan to abolish the Immigration Tribunal, which hears challenges to failed asylum claims, handing the appeals process instead to a team of officials within the Home Office.

The Tories also plan to abolish taxpayer-funded legal aid in immigration cases, with a document on the proposals arguing there “will be no need for lawyers” because claims would be “fairly assessed against the criteria”.

The Conservatives’ plan comes after Reform UK made similar pledges over the summer to take the UK out of the ECHR and deport 600,000 migrants within five years if it won power.

Badenoch sought to portray her party’s plans as more credible, adding that it was backed by “comprehensive legal analysis” in the form of a review by Tory peer and former justice minister Lord Wolfson of Tredegar.

“Reform have nothing but announcements that fall apart on arrival,” she added.

The Tory move to leave the ECHR creates a key dividing line with the Labour government, which has opted against leaving the treaty but is reviewing how it is applied in UK law.

Labour has also pledged tougher action to deal with small boat crossings over the English Channel, which are set to break record numbers this year.

Labour recently set out plans to lengthen refugees’ route to permanent settlement in the UK in a bid to make the country less appealing to migrants, and has negotiated a “one in, one out” pilot scheme with France.

Unlike Reform, the Tories are not promising to formally disapply the Refugee Convention, a 1951 treaty that prevents signatory countries from returning refugees to countries where they face serious threats to their life or freedom.

But the party says it would legislate to prevent courts having regard to it in asylum cases, with a pledge to leave if “activist judges attempt to override Parliament”.