Bright Blue, a group of modernisers who describe themselves as liberal conservatives, has attacked the goal of bringing net migration below 100,000 a year as “arbitrary, indiscriminate and unachievable".
The group’s advisory board includes Damian Green, the Work and Pensions Secretary and former immigration minister; George Freeman, who chairs Ms May’s No 10 policy board; and the former ministers Nicky Morgan, Maria Miller, Nick Boles and Lord (David) Willetts.
It is backed by a total of 140 Tory MPs and peers but insists that not all of its members support its policy proposals.
One senior Tory source said: “A lot of people, including ministers, are saying the manifesto is an opportunity to replace the target with a promise to ensure a sustainable level of net migration. But the person at the top wants to keep it.”
Further doubts about the target have been raised by Steve Hilton, who was David Cameron’s director of strategy in Downing Street.
He admitted Mr Cameron set Ms May “an almost impossible task” of hitting the target when he appointed her Home Secretary in 2010.
He told Bright Blue’s magazine: “That's why she was always looking for ways to restrict immigration, however beneficial the immigration might have actually been in the long term, for example in relation to entrepreneurs.”
He said he did not agree with Ms May’s current approach to migration, arguing that it should “be based on a notion of quality, not quantity”.
A further sign that Ms May is under pressure from her own party on the issue came in a survey of 1,300 Tory members by the ConservativeHome website.
It found that 60 per cent want foreign students taken out of the immigration figures, while 34 per cent said they should remain in the statistics.
James Dobson, researcher at the Bright Blue, told The Independent: “The Prime Minister should abandon the arbitrary, indiscriminate and unachievable net migration target. The public of course still want migration to be controlled.
“This could be better done by introducing new targets – both on gross numbers and the effectiveness of the visa process – for the main different types of migrants: workers, spouses, students, and refugees and asylum applicants.
“If the PM is not prepared to do this, she should, at the very least, remove international students from contributing to the net migration target.”
He said the target meant all immigrants were lumped together, even though the public had differing views on different groups of migrants. Bright Blue’s research found that the public, including a majority of Conservative voters, do not want to see a reduction in many types of migrants including doctors, skilled professional workers, and overseas students.
Mr Dobson added: “International students bring enormous economic benefits, improve the UK’s soft power, and enhance the university experience of UK students. As long as students remain part of the net migration target, which is based on the unreliable International Passenger Survey, the Government has a strong incentive to try and reduce their numbers.”
The Independent and the Open Britain group are running a Drop the Target campaign aimed at persuading the Government to abandon its goal to bring annual net migration down to “tens of thousands”. It stood at 273,000 in the 12 months to last September, during which 134,000 foreign students came to the UK.
Ms May moved last month to dampen speculation that she would change tack after her cabinet ally Karen Bradley, the Culture Secretary, said immigration should be about attracting “the brightest and best” and “not putting numbers on it”.
The Prime Minister said: “We want to see sustainable net migration in this country. I believe that sustainable net migration is in the tens of thousands. Leaving the European Union enables us to control our borders in relation to people coming from the EU, as well as those who are coming from outside.”
Ms May also rebuffed calls from cabinet ministers and Tory backbenchers for overseas students to be removed from the immigration statistics. But they will be measured more accurately in future and Tories have vowed to campaign after the election for them to be taken out of the figures.
Ministers who have called for the students to be omitted include Philip Hammond, the Chancellor; Boris Johnson, the Foreign Secretary and Liam Fox, the International Trade Secretary. But Ms May is said to believe the proposed change would look like “fiddling the figures” and to want to deny Ukip any space to mount a comeback at the general election.
Please sign our petition to call on the Government to Drop The Target:
If you're viewing this on Facebook, please click here for the petition.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies