The letter stopped short of demanding Andy Burnham sacks Shabana Mahmood as Home Secretary

Nearly 80 Labour MPs have written to Andy Burnham to urge him to water down Shabana Mahmood's migration reforms.

In a joint letter to Mr Burnham, the group of backbench Labour MPs warned the Home Secretary's Immigration & Asylum Bill risks "losing progressive voters".

Ms Mahmood was forced to stare down the left of the Labour Party over her reforms, including ex-Deputy Prime Minister Angela Rayner.

However, the Home Secretary is now facing a full-blown migration mutiny.

Writing to Mr Burnham, disgruntled Labour MPs wrote: “Targeting a group of migrants that followed the rules, and applying this retrospectively, does not pass the fairness test for a compassionate but firm system.

"We do not recall being asked on the doorstep to make it harder for migrant workers to settle in the UK.

“Yet we are expending political capital, huge Home Office resource, and losing progressive voters on an indefinite leave to remain reform, which few really understand or want.”

The legislation plans to double the time most migrants have to wait before becoming eligible for indefinite leave to remain and requires asylum seekers to repay some of their taxpayer-funded hotel bills.

Ms Mahmood's reforms will return to the House of Commons on Monday.

The letter is believed to have been orchestrated by Folkestone MP Tony Vaughan.

It stops short of calling for Mr Burnham to sack Ms Mahmood and instead demands a drastic change of direction.

However, an insider told The i Paper: "The Home Secretary, to be frank, is seen as toxic."

A Labour MP also said: “There are profound concerns within the PLP about her [Mahmood’s] proposals.”

However, Mr Burnham's stance on migration has changed considerably since he decided to stand as Labour's candidate in the Makerfield by-election held last month.

He initially came out swinging against Ms Mahmood's proposals earlier this year, echoing Ms Rayner's criticisms.

However, the ex-Greater Manchester Mayor ended up taking a more strident approach while campaigning in the Brexit-backing seat, vowing to cut migration further as Prime Minister.

Ms Mahmood is expected to water down her proposals ahead of Mr Burnham becoming Prime Minister.

The Home Secretary revealed earlier this week that some migrants may receive "special treatment" and be exempt from a settled status crackdown.

She highlighted the prospect of “transitional arrangements” for certain groups of people.

Ms Mahmood also suggested the likes of spouses and older people could be shielded from her plans to double the default qualifying time for permanent residency in the UK.

Mr Burnham, who was backed by 322 Labour MPs when nominations for the ongoing leadership race opened this week, sent a separate letter to his Commons colleagues about his vision.

“I want to create a different culture where MPs are happy and fulfilled doing their jobs, where everyone has a part to play and where opinions and approaches are respected, even where there’s difference,” Mr Burnham said.

“The Whips’ Office should be our HR department, not something to be feared or where discipline is used to stifle debate.”

The Makerfield MP added: “Politics hasn’t been good enough, but I know we can do better.

"Our Government will change the way the country is run: place first, not party first; problem solving, not point scoring."