Analysis: Campaigning on immigration used to be Tory bread and butter, now it's tearing the party apart

The Prime Minister is struggling to battle his own MPs and the plausibility of what he’s promised them.

For time eternal, the Conservative party has lauded itself as having internationalist beliefs, but legitimate concerns about how many foreign nationals come to Britain.

In 2010, a young David Cameron, then leader of the opposition, promised “net migration” would be reduced to the “tens of thousands”. Last year, it was 606,000, the highest figure on record, despite numerous pledges from the Conservatives in the past 13 years to bring those numbers down.

Theresa May as leader, more sensibly promised to reduce figures to a "sustainable" number after Brexit, a pledge impossible to measure, and therefore one you can’t be found to have missed.

Prime Minister Rishi Sunak, who is facing calls from within his own party to further cut immigration.

Now comes Rishi Sunak, who said reducing migration figures is "undoubtedly the country's priority", but has declined to give details, with even the pledge of “stop the boats” containing no real target.

His problem is not the lack of specifics, but more announcing things to a public and party who have been hearing the same thing with no change in outcome for thirteen years.

So now there is a brewing backlash in his own party, coming at a time it was already bruised by the Liz Truss tenure, the prospect of by-elections, and its favourite for London Mayor, Daniel Korski, stepping down over accusations of sexual assault.

On Monday, 25 Tory MPs, calling themselves the New Conservatives group, will put forward a number of proposals called an “alternative manifesto”, including ending the temporary visa scheme for care workers and capping the number of refugees who are allowed to settle in the UK.

The group, which includes the party's deputy chairman, Lee Anderson, claim reducing the number of migrants coming to the country was a key part of victories in the red wall, adding the current level was having "destabilising economic and cultural consequences".

This is not just lobbying for change withing the party, it is a literal alternative manifesto, making up policy they know the Prime Minister cannot adopt.

The report's author, Tory MP Tom Hunt, insisted it was not an attempt to challenge Mr Sunak, and the group wanted to "work with the government constructively”, which seems unlikely when the calls include essentially reducing the number of staff in social care.

The migrant crisis was not caused by the Conservatives, but they have deluded the public and perhaps themselves into thinking they could fix it, introducing policies many Tory MPs think are unworkable, hoping it will convince people they are at least trying.

Last week the UK Government lost in the Court of Appeal, who ruled the government's Rwanda scheme was unlawful. This policy costs £63,000 more per person than letting people settle here, saw £140 million paid to the Rwandan government, and not a single person has been sent.

Mr Sunak is a victim of international law, political reality, and making promises that are entirely unfeasible. His supporters privately are growing frustrated with his political judgement, but are more concerned about the backbenchers in his own party. That Downing Street won’t agree with or condemn the proposals, speaks volumes.

They sense a weak Prime Minister, despite his majority, and one who needs their support to survive. Making more unfeasible pledges is unlikely to do it.