In his first Commons statement, the new prime minister said advisers would work up plans for “an Australian-style points-based system”, declining to set any limit on migrants.

The announcement is a victory for The Independent's Drop the Target campaign launched in April 2017, with the Open Britain group, for the “tens of thousands” policy to be scrapped.

Mr Johnson also repeated his support for an amnesty for existing migrants without documents, acknowledging it could see “perhaps half a million people” gaining the right to remain in the UK.

His announcement of a review cast huge doubt on the government’s existing immigration bill, which is meant to prepare the UK for life after Brexit and end free movement of EU citizens.

It has been attacked for leaving businesses, the NHS and other employers in the dark about a mooted £30,000 salary threshold – a significant clampdown – after cabinet infighting.

In the Commons, Mr Johnson made no mention of the bill, instead telling MPs: “No one believes more strongly than me in the benefits of migration to our country.

Boris Johnson's cabinet: Who's in and who's out Show all 40 1 /40 Boris Johnson's cabinet: Who's in and who's out Boris Johnson's cabinet: Who's in and who's out In: Jacob Rees-Mogg Jacob Rees Mogg appointed Leader of the Commons AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Esther McVey Esther McVey appointed housing secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Jo Johnson Jo Johnson appointed new business and energy secretary EPA Boris Johnson's cabinet: Who's in and who's out In: Brandon Lewis Brandon Lewis appointed immigration secretary Getty Boris Johnson's cabinet: Who's in and who's out In: James Cleverly James Cleverly appointed Conservative Party chairman PA Boris Johnson's cabinet: Who's in and who's out In: Baroness Evans Baroness Evans remains Leader of Lords PA Boris Johnson's cabinet: Who's in and who's out In: Julian Smith Julian Smith appointed Northern Irish secretary Reuters Boris Johnson's cabinet: Who's in and who's out In: Alister Jack Alister jack appointed Scottish secretary PA Boris Johnson's cabinet: Who's in and who's out In: Alun Cairns Alun Cairns remains Welsh secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Grant Shapps Grant Shapps appointed transport secretary Getty Boris Johnson's cabinet: Who's in and who's out In: Alok Sharma Alok Sharma appointed international development secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Robert Buckland Robert Buckland appointed justice secretary Getty Boris Johnson's cabinet: Who's in and who's out In: Amber Rudd Amber Rudd remains work and pensions secretary Getty Boris Johnson's cabinet: Who's in and who's out In: Robert Jenrick Robert Jenrick appointed housing and communities secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Andrea Leadsom Andrea Leadsom appointed business secretary Reuters Boris Johnson's cabinet: Who's in and who's out In: Nicky Morgan Nicky Morgan appointed culture secretary Getty Boris Johnson's cabinet: Who's in and who's out In: Gavin Williamson Gavin Williamson appointed education secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Theresa Villiers Theresa Villiers appointed environment secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Liz Truss Liz Truss is appointed international trade secretary Reuters Boris Johnson's cabinet: Who's in and who's out In: Ben Wallace Ben Wallace appointed defence secretary EPA Boris Johnson's cabinet: Who's in and who's out In: Stephen Barclay Stephen Barclay remains EU secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Dominic Raab Dominic Raab appointed foreign secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Priti Patel Priti Patel appointed home secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Michael Gove Michael Gove given Chandellor of the Duchy of Lancaster AFP Boris Johnson's cabinet: Who's in and who's out In: Sajid Javid Sajid Javid is appointed Chancellor of the Exchequer AP Boris Johnson's cabinet: Who's in and who's out Out: Jeremy Hunt Jeremy Hunt sacked as foreign secretary Reuters Boris Johnson's cabinet: Who's in and who's out In: Matt Hancock Matt Hancock remains health secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out Out: Chris Grayling Chris Grayling resigned as transport secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: Jeremy Wright Jeremy Wright sacked as culture secretary PA Boris Johnson's cabinet: Who's in and who's out Out: Karen Bradley Karen Bradley sacked as Northern Ireland secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: James Brokenshire James Brokenshire sacked as housing and communities secretary Reuters Boris Johnson's cabinet: Who's in and who's out Out: Penny Mordaunt Penny Mourdaunt sacked as defence secretary Reuters Boris Johnson's cabinet: Who's in and who's out Out: Liam Fox Liam Fox sacked as international trade secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: Greg Clarke Greg Clarke sacked as business secretary PA Boris Johnson's cabinet: Who's in and who's out Out: David Mundell David Mundell sacked as Scottish secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: Damien Hinds Damien Hinds sacked as education secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: David Gauke David Gauke resigned as justice secretary EPA Boris Johnson's cabinet: Who's in and who's out Out: Rory Stewart Rory Stewart resigned as international development secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: David Lidlington David Lidlington resigned as deputy Prime Minister PA Boris Johnson's cabinet: Who's in and who's out Out: Philip Hammond Philip Hammond resigned as Chancellor of the Exchequer AFP/Getty

“I am clear that our immigration system must change. For years, politicians have promised the public an Australian-style points-based system.

“And today I will actually deliver on those promises – I will ask the migration advisory committee (MAC) to conduct a review of that system as the first step in a radical rewriting of our immigration system.”

It is the MAC which is supposed to be conducting an “extensive 12-month programme of engagement” with business leaders about the implications of the £30,000 limit.

Other deferred decisions include what benefits EU citizens will be entitled to, whether the pensions of British expats will be updated and new rules for students.

However, the prime minister gave no clues as to how his Australian-style points-based system will work. It was first proposed by the Vote Leave campaign, but dumped by Ms May for being too lax.

Already effectively used for migrants coming from outside the EU, many believe it will fail to cut the numbers coming to the UK if based on education levels, or needs for skills.

Ed Davey, the Liberal Democrats home affairs spokesperson, accused Mr Johnson of a “completely meaningless” announcement, without detail.

“Instead of a plan to fix our immigration system, Johnson is commissioning yet another pointless review,” he said.

“Given that he intends to end EU free movement in just a few months, it’s unacceptable that we still don’t know what he’ll replace it with. Individuals and employers need certainty.”

Mr Johnson first proposed an amnesty for illegal immigrants as mayor of London and confirmed he still advocated it.

“It did not receive an overwhelming endorsement from the previous prime minister when I raised it in cabinet,” he told MPs.