Reported plans that the prime minister is to lift the £30,000 salary cap for immigrants would “unlock the gate to an unlimited inflow of migrants from all over the world” unless the government imposes a sensible immigration cap, a think tank has warned.

The proposal reported by The Times is part of the prime minister’s overhaul of immigration procedures post-Brexit, where he is said to be pursuing an Australian-style immigration system.

Other criteria of the points-based system — unveiled in the manifesto and by ministers ahead of the December 2019 election — for entry would include English language proficiency, age, and education level. While The Times reports that salary may be a factor in assessing applications, a former Conservative Party leader warned that it would make it difficult for Boris Johnson to fulfil his pledge to “take back control of our borders”.

Iain Duncan Smith said: “They should be cautious about ditching the £30,000 threshold. They will need to have very strong checks in place to ensure that they deliver on their pledge to control immigration.”

Though often quoted as an “Australian-style” points-based immigration system, there is a marked difference between Australia’s and that of the Conservative Party in that the Australian system has a cap on the maximum number of immigrants allowed into the country, which is currently set at a modest 160,000 per year.

Mass migration sceptic think tank Migration Watch UK warned that without a cap on immigrants, it would be impossible to control migration.

In a statement seen by Breitbart London, Dr Ben Greening, Executive Director of Migration Watch UK, said: “The reported removal of a salary requirement for skilled migrants would be extremely unwise. It would unlock the gate to an unlimited inflow of migrants from all over the world.

“To guard against this, the government must ensure an Australian-style cap on numbers is included, otherwise immigration could rapidly run further out of control, as we have seen in the past.”

In early January, a study from Migration Watch UK suggested that Johnson’s points-based system may result in a rise in immigration numbers, saying the changes “would expose between six and nine million UK jobs to new or increased global competition”.

While Mr Johnson is reported to have said during the Cabinet meeting on Tuesday, at which the plans were unveiled, that he would reduce overall immigration, there is no committed figure in the manifesto by which citizens can measure whether the prime minister had kept to his word.

Unlike in three previous Tory election manifestos — which pledged to reduce net migration from “the hundreds of thousands to the tens of thousands”, and which successive Tory governments failed to fulfil — Boris’s 2019 manifesto ditched the cap entirely, leading to criticisms from Brexit Party leader Nigel Farage, who said: “Yet more meaningless manifesto pledges from the Conservatives on immigration. Will they cut numbers or raise them? It seems they have given up on the former.”