Nigel Farage has unveiled the Brexit Party's general election policies, promising a "political revolution that puts ordinary people first".
The party leader pledged to halve the foreign aid budget, abolish the House of Lords and cap permanent immigration at 50,000 a year.
The Brexit Party is running in 275 seats, after deciding to stand down in the 317 won by the Tories in 2017.
It is also promising a "clean break" from all EU institutions.
Speaking in London, Mr Farage said his party would scrap VAT on fuel bills and stop companies earning less than £10,000 a year paying corporation tax.
He promised millions of trees would be planted to absorb carbon emissions.
Mr Farage said his party would save tens of billions of pounds by redirecting foreign aid, scrapping the HS2 rail project and stopping the UK's contributions to the EU.
He also claimed the party could recover £7bn from the UK's share of capital at the European Investment Bank.
Mr Farage said he favoured making civil servants sign a "pledge of political neutrality" and devising "political guidelines" for the Supreme Court.
He added that any Brexit Party MPs elected would "hold Boris Johnson to his word" over Brexit, and act as "new radicals" in Parliament to "change politics for good".
Mr Farage accused the Conservatives of having "no intention" of reducing immigration numbers, as firms that supported them wanted "cheap labour".
"We would very much want to get immigration numbers down to what for 60 years were very acceptable and very workable post-war levels," he said. "Yes, I'm talking around about 50,000 people a year."
Mr Farage added that work permits would give "flexibility" to the system, as there was a difference between permanent settlement and allowing workers to come for a "time-limited period".
- Introducing a ban on exporting waste to other countries for it to be burned
- Providing free "base level" broadband for deprived regions, and free wi-fi on all public transport
- Abolishing business rates for shops outside the M25, funded by a "small online sales tax"
- Scrapping all interest on student loans, and abolishing inheritance tax
- Phasing out the BBC licence fee
- Limiting postal voting to people who are elderly, infirm or overseas
Several other political parties have launched traditional manifestos - outlining policy commitments for government - this week, but Mr Farage and his colleagues have declined to do so.
The former UKIP leader, who is not standing as a candidate in the election, said manifestos were a "means of telling people what they want to hear without ever having the genuine desire to implement them".
Instead, he said his party would be making a "contract with the people" containing a "targeted set of deliverable pledges".
The Brexit Party has changed its tune on, yes, Brexit.
Until a few weeks ago its leader, Nigel Farage was saying a no-deal Brexit was the "only acceptable deal".
But this "contract" moves the goalposts.
Gone is the criticism of Boris Johnson's withdrawal agreement - now the party simply promises there will be "no extended transition period" after Brexit.
Without saying so explicitly in this document, the Brexit Party is warning that it will campaign to ensure Mr Johnson sticks to his promise not to extend the transition any further.
What are the other parties pledging on Brexit, immigration and trees?
Brexit: The Conservatives say they will deliver Brexit by the end of January 2020 under the terms of the PM's deal negotiated with the EU.
The Liberal Democrats have vowed to cancel Brexit if elected as a majority government, or otherwise campaign for a referendum including the option of staying in the EU.
Labour wants to renegotiate the PM's Brexit deal then put it to a referendum within six months, with the option of staying in the EU. The party has not said which side it would take in such a vote.
The SNP wants Scotland to stay in the EU.
Immigration: Labour has not set a target in its manifesto, but has pledged to regulate the labour market to stop the "undercutting of wages and conditions".
For the Tories, Home Secretary Priti Patel has previously said overall immigration should come down, but not according to an "arbitrary" target.
Boris Johnson has promised to reduce unskilled migration.
The SNP says cutting immigration would damage the Scottish economy.
Trees: The Conservatives have said they will plant 30 million trees a year by 2025 if they win the election.
The Liberal Democrats have pledged to plant twice as many trees in the same period.
Labour has promised an "ambitious programme of tree planting", including a forest of a million trees to help the NHS become carbon neutral.
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