Media playback is unsupported on your device Media caption Welfare cuts and the rocketing cost of rent were leading to a "social cleansing" of central London, said Mr Corbyn

MPs have backed government plans for £12bn in welfare cuts, but acting Labour leader Harriet Harman suffered a significant rebellion in the vote.

The Commons backed the Welfare Reform and Work Bill by 308 to 124 votes.

Forty-eight Labour MPs defied orders to abstain and instead voted against the bill, which includes plans to limit child tax credit to two children.

Rebels included leadership hopeful Jeremy Corbyn and London mayoral candidates Sadiq Khan and David Lammy.

Of the 53 Labour MPs first elected to Parliament in May, 18 opposed the bill.

During a five-hour debate, Labour MP John McDonnell said he would "swim through vomit" to oppose the legislation.

However, a Labour amendment seeking to derail the legislation was defeated by 308 votes to 208.

Ms Harman has faced criticism for her stance, with many MPs saying she should have been more outspoken in her opposition to curbs on child tax credits and cuts to other in-work benefits.

Mr Corbyn's three Labour leadership rivals - Andy Burnham, Yvette Cooper and Liz Kendall - followed Ms Harman's lead and abstained.

Media playback is unsupported on your device Media caption The Labour Party is in "bewilderment" and "emotional trauma" following its election defeat, David Blunkett says

Reacting to the vote, Labour MP Diane Abbott tweeted: "Just voted against Tory welfare bill. Sorry for colleagues who knew it was wrong but abstained. We weren't sent to Parliament to abstain."

Conservative MP and chief secretary to the Treasury Greg Hands tweeted: "47 Labour rebels on welfare tonight. Huge. Biggest Labour rebellion for some time. Leadership crisis without actually having a Leader!"

BBC assistant political editor Norman Smith said things could not be much worse for Labour, with a fifth of the party openly defying the leadership and many more "deeply unhappy".

He told BBC Radio Four's Today programme the split ran "right up through the party, to the shadow cabinet".

The vote showed about half of the new intake were "well to the left of the mainstream", which tells us that the gravitational pull of the party is not back to the centre, but to the left, he added.

He said one of Ms Harman's aides had told him that whoever takes over as party leader has a "hell of a job on their hands".

'Nauseating'

But Mr Corbyn said the revolt had "strengthened" Labour's position against the Conservatives.

He told BBC Radio 4's Today programme society ought to be "deeply concerned" about child poverty and deprivation levels.

Media playback is unsupported on your device Media caption Diane Abbott: "Outside of Westminster, Labour supporters think this is a bad bill"

Former Labour Home Secretary David Blunkett, who also served as work and pensions secretary, said the party was in "emotional trauma", and was "not debating enough about where we go from here".

"Last night again focused on us being divided," he said, adding that the Welfare Bill was "clearly not a moment for setting out the alternative".

MPs who won their seats in May were "very lucky" and should ask themselves "why others didn't", he added.

Analysis by Ross Hawkins, BBC political correspondent

Image copyright AP

First Harriet Harman took a stand - saying Labour had to wake up and listen to voters on welfare.

Then she compromised - tabling an amendment designed to sidestep a row. And then almost 50 rebels ignored her instructions.

Were she Labour's permanent leader, her authority would be in tatters.

But it's not about her; she'll be gone by the autumn.

The real question is: could any of her would-be successors persuade the party that welfare must be reformed now?

Would they want, or dare, to try?

Read Ross's analysis in full

The bill, which also seeks to lower the overall household benefit cap from £26,000 a year to £20,000 outside of London, and £23,000 in London, as well as to train a further three million apprentices, has now cleared its first parliamentary hurdle and will move on to more detailed scrutiny.

In a passionate debate, Conservative MPs lined up to support the measures.

As well as Labour MPs who did not support the bill, it was opposed by the SNP, the Liberal Democrats, Plaid Cymru and the Greens.

Mr McDonnell said: "I would swim through vomit to vote against this bill and listening to some of the nauseating speeches tonight I think we might have to.

"Poverty in my constituency is not a lifestyle choice, it is imposed upon people.

"We hear lots about how high the welfare bill is, let's understand why that's the case.

"The housing benefit bill is so high because for generations we've failed to build council houses, we've failed to control rents, we've done nothing about the 300,000 properties that stand empty in this country."

SNP employment spokeswoman Hannah Bardell said it was "disgraceful" that Labour had not joined her party in opposing the bill.

"Labour had the perfect opportunity to join the SNP in a progressive coalition to oppose the Tories - but with some honourable exceptions they sat on their hands," she said.

On Twitter, SNP MP Pete Wishart said it was "apparent" that Labour and the SNP together could have defeated the bill.

Tim Farron, in his first Commons speech as Liberal Democrat leader, said his party was voting against the "unfair, unwise and inhuman" proposals.

Work and Pensions Secretary Iain Duncan Smith said Labour was beset by "internal fear and loathing" and that the bill would put welfare funding on a "more sustainable footing" while protecting those most in need.

Speaking after the vote, he said: "Nearly 50 Labour MPs have defied their leadership and opposed our welfare reforms which will move our country from a low wage, high tax and high welfare economy to a higher wage, lower tax and lower welfare society.

"It's clear that Labour are still the same old anti-worker party - just offering more welfare, more borrowing and more taxes."

MPs who voted against the bill

Abbott, Diane - Labour MP for Hackney North and Stoke Newington

Abrahams, Debbie - Labour MP for Oldham East and Saddleworth

Ahmed-Sheikh, Tasmina - SNP MP for Ochil and South Perthshire

Anderson, David - Labour MP for Blaydon

Arkless, Richard - SNP MP for Dumfries and Galloway

Bardell, Hannah - SNP MP for Livingston

Black, Mhairi - SNP MP for Paisley and Renfrewshire South

Blackford, Ian - SNP MP for Ross, Skye and Lochaber

Blackman, Kirsty - SNP MP for Aberdeen North

Boswell, Philip - SNP MP for Coatbridge, Chryston and Bellshill

Brake, Tom - Lib Dem MP for Carshalton and Wallington

Brock, Deidre - SNP MP for Edinburgh North and Leith

Brown, Alan - SNP MP for Kilmarnock and Loudoun

Burgon, Richard - Labour MP for Leeds East

Butler, Dawn - Labour MP for Brent Central

Cameron, Dr Lisa - SNP MP for East Kilbride, Strathaven and Lesmahagow

Campbell, Gregory - DUP MP for East Londonderry

Carmichael, Alistair - Lib Dem MP for Orkney and Shetland

Chapman, Douglas - SNP MP for Dunfermline and West Fife

Cherry, Joanna - SNP MP for Edinburgh South West

Clegg, Nick - Lib Dem MP for Sheffield Hallam

Clwyd, Ann - Labour MP for Cynon Valley

Corbyn, Jeremy - Labour MP for Islington North

Cowan, Ronnie - SNP MP for Inverclyde

Crawley, Angela - SNP MP for Lanark and Hamilton East

Davies, Geraint - Labour MP for Swansea West

Day, Martyn - SNP MP for Linlithgow and East Falkirk

Docherty, Martin John - SNP MP for West Dunbartonshire

Dodds, Nigel - DUP MP for Belfast North

Donaldson, Jeffrey M - DUP MP for Lagan Valley

Donaldson, Stuart - SNP MP for West Aberdeenshire and Kincardine

Dowd, Peter - Labour MP for Bootle

Durkan, Mark - SDLP MP for Foyle

Edwards, Jonathan - Plaid Cymru MP for Carmarthen East and Dinefwr

Farron, Tim - Lib Dem MP for Westmorland and Lonsdale

Fellows, Marion - SNP MP for Motherwell and Wishaw

Ferrier, Margaret - SNP MP for Rutherglen and Hamilton West

Flynn, Paul - Labour MP for Newport West

Gethins, Stephen - SNP MP for North East Fife

Gibson, Patricia - SNP MP for North Ayrshire and Arran

Glindon, Mary - Labour MP for North Tyneside

Godsiff, Roger - Labour MP for Birmingham, Hall Green

Goodman, Helen - Labour MP for Bishop Auckland

Grady, Patrick - SNP MP for Glasgow North

Grant, Peter - SNP MP for Glenrothes

Gray, Neil - SNP MP for Airdrie and Shotts

Greenwood, Margaret - Labour MP for Wirral West

Haigh, Louise - Labour MP for Sheffield, Heeley

Harris, Carolyn - Labour MP for Swansea East

Hayman, Sue - Labour MP for Workington

Hendry, Drew - SNP MP for Inverness, Nairn, Badenoch and Strathspey

Hosie, Stewart - SNP MP for Dundee East

Hussain, Imran - Labour MP for Bradford East

Jones, Gerald - Labour MP for Merthyr Tydfil and Rhymney

Jones, Helen - Labour MP for Warrington North

Kaufman, Sir Gerald - Labour MP for Manchester Gorton

Kerevan, George - SNP MP for East Lothian

Kerr, Calum - SNP MP for Berwickshire, Roxburgh and Selkirk

Khan, Sadiq - Labour MP for Tooting

Kinahan, Danny - UUP MP for South Antrim

Lamb, Norman - Lib Dem MP for North Norfolk

Lammy, David - Labour MP for Tottenham

Lavery, Ian - Labour MP for Wansbeck

Law, Chris - SNP MP for Dundee West

Lewis, Clive - Labour MP for Norwich South

Long Bailey, Rebecca - Labour MP for Salford and Eccles

Lucas, Caroline - Green MP for Brighton, Pavilion

MacNeil, Angus Brendan - SNP MP for Na h-Eileanan an Iar

Marris, Rob - Labour MP for Wolverhampton South West

Maskell, Rachael - Labour MP for York Central

Mc Nally, John - SNP MP for Falkirk

McCaig, Callum - SNP MP for Aberdeen South

McDonald, Andy - Labour MP for Middlesbrough

McDonald, Stewart - SNP MP for Glasgow South

McDonald, Stuart C - SNP MP for Cumbernauld, Kilsyth and Kirkintilloch East

McDonnell, Dr Alasdair - SDLP MP for Belfast South

McDonnell, John - Labour MP for Hayes and Harlington

McGarry, Natalie - SNP MP for Glasgow East

McInnes, Liz - Labour MP for Heywood and Middleton

McLaughlin, Anne - SNP MP for Glasgow North East

Meacher, Michael - Labour MP for Oldham West and Royton

Mearns, Ian - Labour MP for Gateshead

Monaghan, Carol - SNP MP for Glasgow North West

Monaghan, Dr Paul - SNP MP for Caithness, Sutherland and Easter Ross

Moon, Madeleine - Labour MP for Bridgend

Morris, Grahame M - Labour MP for Easington

Mulholland, Greg - Lib Dem MP for Leeds North West

Mullin, Roger - SNP MP for Kirkcaldy and Cowdenbeath

Newlands, Gavin - SNP MP for Paisley and Renfrewshire North

Nicolson, John - SNP MP for East Dunbartonshire

O'Hara, Brendan - SNP MP for Argyll and Bute

Osamor, Kate - Labour MP for Edmonton

Oswald, Kirsten - SNP MP for East Renfrewshire

Paisley, Ian - DUP MP for North Antrim

Paterson, Steven - SNP MP for Stirling

Pearce, Teresa - Labour MP for Erith and Thamesmead

Pugh, John - Lib Dem MP for Southport

Rimmer, Marie - Labour MP for St Helens South and Whiston

Ritchie, Margaret - SDLP MP for South Down

Robertson, Angus - SNP MP for Moray

Salmond, Alex - SNP MP for Gordon

Saville Roberts, Liz - Plaid Cymru MP for Dwyfor Meirionnydd

Shannon, Jim - DUP MP for Strangford

Sheppard, Tommy - SNP MP for Edinburgh East

Sherriff, Paula - Labour MP for Dewsbury

Siddiq, Tulip - Labour MP for Hampstead and Kilburn

Skinner, Dennis - Labour MP for Bolsover

Smith, Cat - Labour MP for Lancaster and Fleetwood

Stephens, Chris - SNP MP for Glasgow South West

Stevens, Jo - Labour MP for Cardiff Central

Stringer, Graham - Labour MP for Blackley and Broughton

Thewliss, Alison - SNP MP for Glasgow Central

Thomson, Michelle - SNP MP for Edinburgh West

Weir, Mike - SNP MP for Angus

Whiteford, Dr Eilidh - SNP MP for Banff and Buchan

Whitford, Dr Philippa - SNP MP for Central Ayrshire

Williams, Hywel - Plaid Cymru MP for Argon

Williams, Mr Mark - Lib Dem MP for Ceredigion

Wilson, Corri - SNP MP for Ayr, Carrick and Cumnock

Wilson, Sammy - DUP MP for East Antrim

Winnick, David - Labour MP for Walsall North

Wishart, Pete - SNP MP for Perth and North Perthshire

Wright, Iain - Labour MP for Hartlepool

Zeichner, Daniel - Labour MP for Cambridge