David Cameron today refused to apologise for threatening to slash a further £4.4billion from disability benefits - plans that were ditched just 48 hours after last week's Budget.

Labour leader Jeremy Corbyn demanded the Prime Minister say sorry to more than 600,000 disabled people who 'went through such anguish and upset' after George Osborne announced he was cutting benefits to people who need help dressing, undressing or using the bathroom.

As the two leaders clashed in the Commons, disabled people were staging a protest outside the chamber and parliamentary authorities caused fury by telling demonstrators not to take photos.

Stewards even locked the doors to the Commons chamber to stop disabled protesters storming in as they chanted: 'No more deaths from benefit cuts'.

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David Cameron (pictured at Prime Minister's Questions today) refused to apologise for threatening to slash a further £4.4billion from disability benefits - plans that were ditched just 48 hours after last week's Budget

As the two leaders clashed in the Commons, disabled people were staging a protest outside the chamber and parliamentary authorities caused fury by telling demonstrators not to take photos

Mr Cameron admitted the Government does 'not always get every decision right' and pledged to 'learn the lessons' from the embarrassing U-turn, but repeated Mr Osborne's defiant response to calls to apologise by insisting the Treasury was increasing spending on disability benefits.

He also refused to say how the Chancellor will make up the £4.4billion shortfall created by ditching the planned disability benefits cuts.

The plans to reduce personal independence payments (PIP) - which are paid to 640,000 disabled people in Britain - triggered the resignation of Iain Duncan Smith as Work and Pensions Secretary and sent the Tories into its worst infighting in two decades.

After scores of Tory MPs threatened to inflict an embarrassing rebellion on the Government over the plans, ministers backed down and on Monday announced there were no plans to make any further welfare plans before 2020.

At Prime Minister's Questions today Mr Corbyn read out a letter he had received from a disabled person named 'Adrian'.

Jeremy Corbyn (pictured at Prime Minister's Questions today) read out a letter he had received from a PIP claimant named 'Adrian' who said he lived in 'constant fear of my benefits being reassessed and stopped and being forced onto the streets'

Mr Corbyn read out a letter he had received from a PIP claimant named 'Adrian' who said he lived in 'constant fear of my benefits being reassessed and stopped and being forced onto the streets'.

The Labour leader asked: 'Could the Prime Minister do what the Chancellor failed to do yesterday and apologise to those that went through such anguish and upset during the threats of the cuts in their personal independence payments?’

Mr Cameron replied: 'When you are faced with having to take very many very difficult decisions including very many spending reductions as we were after becoming the Government after 2010, you do not always get every decision right.

'I’m the first to accept that, to admit that and on every occasion that happens it’s very important you learn the lessons.

'As we do so we will continue to increase spending on disability benefits which will be more than £46billion a year by the end of this Parliament compared to £42billion when I became the Prime Minister.'

As the protest outside grew louder, Commons authorities decided to lock the doors to the Commons chamber to avoid a repeat of scenes from last summer when disabled protesters tried to storm into the chamber during Prime Minister's Questions.

Locking the doors caused a delay for MPs trying to exit the chamber after Prime Minister's Questions.

Stewards even locked the doors to the Commons chamber to stop disabled protesters storming in as they chanted: 'No more deaths from benefit cuts'

Yesterday Mr Osborne fought his corner over the U-turn, insisting he would 'listen and learn' from Budget mistakes but struck an aggressive tone as he addressed MPs on his 'botched' plans.

He said he would not break the Tory manifesto pledge by targeting benefits handed to wealthy pensioners to plug the shortfall.

Mr Osborne blasted Labour for ruining the public finances but dodged repeated calls for him to apologise for the about-turn on plans to slash personal independence payments (PIP) handed to more than 600,000 disabled people who need help dressing, undressing or using the bathroom.

The policy prompted the resignation of Iain Duncan Smith as work and pensions secretary and triggered days of bitter Tory infighting about the direction of the Government.

Chancellor George Osborne struck an aggressive tone yesterday as he faced MPs for the first time since dropping a major part of his Budget

Alternative cuts have not been identified - beyond a promise not to find them in the welfare budget - meaning MPs were asked to pass a Budget missing its biggest revenue raiser.

Mr Osborne had faced calls from Tory MPs to make up the £4.4billion shortfall in the welfare bill by cutting the free bus passes, TV licences and winter fuel allowance given to all pensioners regardless of their income, but Mr Osborne ruled this out today.

Labour has demanded Mr Osborne quit as Chancellor over the row.

Mr Osborne conceded the debate over his eighth Budget had been 'lively' but insisted: 'Let's be clear: The key principles behind this Budget are if we are going to deliver a strong and compassionate society for the next generation we have to live within our means, we have to back business to create jobs.

'And we have to make sure work pays by putting more money into the pockets of working people.

'That is what we committed to in our manifesto, that is what the British people elected us to deliver, that is what this Budget does.'

The Chancellor, seen yesterday leaving Downing Street, took the rare step of leading a Budget debate amid claims he 'botched' the plans

Mr Osborne said he was 'sorry' Mr Duncan Smith had resigned over the Budget measures and praised his 'achievements' in office.

He said: 'The decisions we made to keep our economy secure are always difficult and where we don't get them right I have always been prepared to listen and learn.'

As he attempted to get back on the front foot, Mr Osborne claimed his Budget did mean 'we are all in it together'.

Mr Duncan Smith used the phrase in his explosive resignation letter last week in a furious attack on the Government for undermining social justice in Britain.

Challenged to apologise by former shadow chancellor Chris Leslie, Mr Osborne said: 'Where we have made a mistake, where we have got things wrong, we listen and we learn - that's precisely what we have done.

'But where is the apology from the Labour Party?'

Corbyn ally Diane Abbott dismissed noisy support for Mr Osborne on the Conservative benches as 'Tory boys' who want to get 'into NO 10 good books'

Mr Osborne's speech was praised by Tory grandee Sir Nicholas Soames who reserved harsh criticism for shadow chancellor John McDonnell

Mr Osborne refused to spell out where he would find alternative savings, insisting the Government would take its time and revise its welfare cap in light of the new forecasts at the autumn statement.

In his reply, shadow chancellor John McDonnell blasted: 'Don't tell us we are all in this together'.

He slammed the Chancellor's actions as those of 'the grubby, incompetent manipulations of a political chancer'.

And turning to Mr Duncan Smith - ignored by Labour leader yesterday - Mr McDonnell said: 'I do not agree with a single policy he pursued - but I do not doubt his sincerity.'

The exchanges turned angry as two Tory MPs linked Mr McDonnell's alleged support for the IRA to the Brussels attacks - prompting the Speaker to intervene.

Tom Tugendhat, the Tory MP for Tonbridge, said: 'He stands with bombers who murdered my friends in N Ireland.'

Earlier, Robert Chote, the head of the Officer for Budget Responsibility, said that following the decision to cancel the PIP cuts, the Government was now set to exceed its own welfare cap by £4 billion a year.

Stephen Crabb, left, the new work and pensions secretary, arrived in Downing Street yesterday for the first Cabinet meeting since Iain Duncan Smith resigned. Also seen today was Foreign Secretary Philip Hammond

He told the Commons Treasury committee: 'Taking into account the loss of the money from PIP, you breach by about £4 billion in most years.

'It bobs up and down, but it is essentially £4 billion a year.'

Mr Osborne faced charges yesterday that he was 'hiding' from MPs questions about his 'botched Budget' when he sent junior minister David Gauke to answer a Commons urgent question.

His appearance today comes a day after Stephen Crabb, the new work and pensions secretary, confirmed the Government would not replace controversial cuts to the personal independence payment (PIP) with other welfare savings.

Boris Johnson last night piled on the pressure by describing the policy as a 'mistake'.

The policy, which would have raised £1.3billion a year by 2019/20, prompted the explosive resignation of Mr Duncan Smith on Friday night and its cancellation leaves a black hole in Mr Osborne's plans.

The Cabinet met this morning for the first time since Mr Duncan Smith's resignation.

The Chancellor praised the former work and pensions secretary, echoing David Cameron's attempt yesterday to call a truce on the Tory infighting.

Environment Secretary Liz Truss, left, Home Secretary Theresa May, centre, and Defence Secretary Michael Fallon, right, were all seen in Downing Street yesterday ahead of the Cabinet

Mr Osborne said: 'As Conservatives, we know that those who suffer most when Britain loses control of its public finances and the economy crashes aren't the best off but the poorest and the most vulnerable.

'That's what's informed all we have done over the last six years and was at the heart of the manifesto we were elected to deliver.

'I'm sorry Iain Duncan Smith chose to leave the Government last week, and want to recognise his achievements in helping to make sure work pays, breaking the old cycles of welfare dependency and ensuring the most vulnerable in our society are protected.

'That's work this government will go on doing.'

Mr Osborne added: 'We were elected by the British people a year ago on a manifesto that committed to economic security, controlling public spending and lower taxes for working people and business, precisely because we know that is how we deliver more opportunity in our society.

That is the commitment we are delivering in this Budget.

'It is a Budget of a compassionate, one nation Conservative Government determined to deliver both social justice and economic security.

'It's a Budget that puts the next generation first.'

Shadow chief secretary Seema Malhotra said Mr Osborne had to answer questions about what would fill the blackhole in his plans.

She said: 'The Tories are in disarray over their unfair Budget.

'Vague promises of 'no plans' to make further welfare cuts are not good enough. Given the Tories' record of unfairness we need clear answers from George Osborne on who will pick up the bill for his failure and what this mess means for his already discredited fiscal rule.'

Ministers have been asked 17 times how to fill the gap in the Budget left by the U-turn on personal independence payments.

Boris Johnson appeared in Downing Street yesterday as he was due to attend a meeting of the political cabinet in Downing Street

London Mayor Mr Johnson last night piled the pressure on Mr Osborne by describing the PIP plans as a 'mistake'.

He told ITV's The Agenda: 'I think I have already said very clearly that the Government has decided collectively and quite rightly to take the PIP aspect of it [the Budget] and try to sort it out.

'It's obvious from what's happened that it's admitted that it was a mistake.'

Mr Osborne presented his Budget, pictured, less than a week ago but yesterday explained to MPs how to defend his plans

Former Chancellor Ken Clarke today played down the row and told the BBC it was 'absurd' to reduce the Budget to right between Mr Osborne and Mr Duncan Smith.

Mr Clarke said it was 'quite right' for spending to be higher now than it was when he was in No 11.

But he said: 'I mean we have reached the astonishing position where we're paying out more to disabled people by benefits than the entire budget of the Ministry of Defence.'

Mr Clarke added: 'What (Mr Osborne) should do is explain the underlying strategy about why we need to tackle the deficit.

'Creeping into the debate about policy is somehow we don't need to bother, that money is cheap, let's just borrow it, tax should be things that only go down and spending that only goes up and we don't challenge any of the powerful lobbies that exist nowadays.'

Former Tory leader William Hague today slammed Mr Duncan Smith's resignation.

Writing in the Telegraph, he said: 'Iain's resignation was very much the wrong thing to do, for himself, his work, his party and his country.

'It was wrong for him because whatever the outcome of the EU referendum in June, he could have moved to another department, leaving behind a distinguished record on welfare reform, and applied himself to new tasks in a government that needed him.

'It was wrong for his work because many of his essential changes, such as the hugely popular cap on welfare payments that had grown out of control, will now be defined in the minds of many by his parting attack on the Government's policies, rather than by his advocacy of those same policies for the last six years.'