Labour at war over migrants and economy: Cabinet ministers trade blows on eve of Burnham's crunch party conference... so is the PM's honeymoon finally over?

Labour descended into open warfare over immigration and the economy on Saturday night, souring Andy Burnham's first party conference as Prime Minister.

Cabinet ministers are at loggerheads over a planned crackdown on migrant visas, while another grandee blasted the leadership for putting union demands ahead of economic growth.

The very public rows threaten to overshadow what Mr Burnham had planned would be a triumphant party conference, which gets under way in Liverpool on Sunday.

Those hopes took a blow when Angela Rayner doubled down on her criticism of Home Secretary Shabana Mahmood's plans to make it harder for migrants to gain permanent residence in the UK, which she previously branded 'un-British'. 

One Labour MP called the former deputy prime minister's fresh intervention a 'drive-by shooting', while a senior party official told The Mail on Sunday: 'It's quite mad she's chosen this moment to attack.'

The row deepened on Saturday when fellow Cabinet minister Lisa Nandy issued a stern slapdown of Ms Rayner by publicly backing Ms Mahmood.

Meanwhile, another MP suggested that Mr Burnham 'remind [Rayner] of the benefits of keeping her mouth closed'.

Opening a separate front, former business secretary Peter Kyle accused the Prime Minister of not doing enough to boost growth.

Andy Burnham pictured with his wife Marie-France van Heel in Liverpool. Labour descended into open warfare over immigration and the economy on Saturday night

Angela Rayner, pictured in Liverpool on Saturday, criticised Home Secretary Shabana Mahmood's plans to make it harder for migrants to gain permanent residence in the UK

He said Mr Burnham needed to act with 'more urgency' and should delay expansions to workers' rights demanded by the party's union paymasters that would tie businesses up in more red tape.

Mr Kyle, a close ally of Sir Keir Starmer, compared Britain's ailing economy to a car 'on a motorway driving in the right direction but only at 30mph', adding: 'Why wouldn't we put our foot down and get there quicker?'

The bitter rows dividing the party come as:

• Insiders say Mr Burnham is still planning a snap election, despite claims he had 'bottled it', claiming the PM's promised 'ten-year plan' is a 'Trojan horse' for a manifesto;
• Up to 100 MPs have joined a new group of rebels, led by former minister Darren Jones, who are 'ready to pounce' on Mr Burnham if his leadership falters;
• Labour sources warned that Mr Burnham 'doesn't have the balls' to face down union demands to 'spend, spend, spend';
• Mr Burnham's wife Marie-France van Heel quit her job as a senior marketing executive so she can support the Prime Minister full-time as an effective 'first lady'.

Housing Secretary Ms Rayner fired the first shots of the civil war on Saturday by insisting the visa clampdown effectively 'changed the goalposts' for migrants already living in Britain, particularly those working in social care.

A senior party official suggested Ms Rayner intended her intervention to win her more support within Labour's rank and file, as her profile was in decline since Louise Haigh became de facto deputy PM in July. 

The well-placed insider said: 'She's unhappy that she doesn't have as much support as she did in her last stint – obviously because she isn't DPM and that hasn't sunk in. Her nose is out of joint with all the influence Lou has.'

Culture Secretary Ms Nandy sided with the Home Secretary on Radio 4's Today programme on Saturday. She said Ms Mahmood was 'taking great care... and she has the support of the Cabinet in doing so'.

As Labour's internal strife played out, Tory leader Kemi Badenoch said: 'If Andy Burnham's Cabinet are already at war with each other over small changes to the immigration system, how can they ever be trusted to stop the boats?'

Meanwhile, Labour peer Lord Glasman, founder of the party's Blue Labour movement, called for an end to the infighting.

He said: 'I would expect all ministers to act within the framework of collective responsibility. It is clear that Shabana Mahmood's approach is the right one.

'People are rightfully concerned about illegal migration as well as the scale of legal migration. This government's fate lies in whether it has the courage to confront that.'

But privately some party insiders expressed doubt that Mr Burnham has the resolve to back Ms Mahmood's reforms. One said: 'I'm afraid the Prime Minister strikes me as utterly confused.'

Further exposing divisions in the party, Ms Rayner received public support from Folkestone MP Tony Vaughan. He said she was 'right' to object to the changes, which would see new arrivals to the UK have to wait ten, or even 15, years to be granted indefinite leave to remain, up from the current five.

He said: 'Why should workers on health and social care visas who have come here to look after our loved ones have to wait 15 years for settlement? It is economically and morally wrong and will damage our health and social care system.'

Mr Kyle's critical comments on Mr Burnham's economic agenda marked his first public intervention since leaving government.

He said that while Labour had 'inherited a growth emergency' from the Tories, he believes 'that emergency persists' two years on.

Mr Kyle said the Government must be willing to take decisions that involve 'short-term' pain in return for longer-term economic gain – including delaying the planned expansion of workers' rights championed by Ms Rayner.

He argued: 'We might need to look and have honest conversations with unions about how we sequence some of the rights... to make sure that we get growth into the economy in the shorter term.'

One of Labour's big plans for an economic boost hit a major setback on Saturday night as it was announced that Heathrow's third runway is likely to be delayed until 2039, four years later than first planned.

Privately some party insiders expressed doubt that Mr Burnham has the resolve to back Ms Mahmood's reforms (Pictured: Ms Mahmood on September 15)

Mr Burnham hoped to get his first conference as Labour leader back on track on Saturday night, with a new pledge to help people on to the property ladder.

The Prime Minister said October's Budget will introduce a new equity loan scheme for first-time buyers, which mean they will require just a 2.5 per cent deposit.

The plan, akin to the Tories' Help to Buy scheme, will provide a 20 per cent equity loan on new-build homes, with an initial interest-free period. The funding, Labour say, will come from 'reprioritising existing government budgets'.

On an average first-time home costing £230,000, a buyer could put down a deposit of £5,750 and access a loan of up to £46,000.