Politicians and campaigners are calling for a radical overhaul of housing policy in London after The Independent revealed that 50,000 homeless families have been pushed out of boroughs.

Natalie Bennett, the leader of the Green Party, described the impact of out-of-borough placements on vulnerable families as a “toll of misery”.

Sadiq Khan, Labour’s shadow London minister, said the figures are “a badge of shame” for the Coalition Government, calling on the next mayor of London to “conduct a root and branch review of housing in London if we are to end this scandal”.

The Independent has revealed leaked figures showing that London councils had dumped 49,789 families out of borough between July 2011 and July 2014. Some 2,707 families have been moved out of Greater London entirely over the past two years.

General election 2015: The worst gaffes and controversies Show all 36 1 /36 General election 2015: The worst gaffes and controversies General election 2015: The worst gaffes and controversies 4 May: Milibrand part 2 Russell Brand dramatically unveiled the second part of his interview with Ed Miliband, in which he agreed with the leader and then called on his YouTube viewers to vote Labour. David Cameron had described him as a "joke" who previously advocated not voting - but with Brand commanding more than a million YouTube subscribers that may come back to haunt the Tories. General election 2015: The worst gaffes and controversies 3 May: #EdStone Labour leader Ed Miliband unveiled Labour's pledges carved into a stone plinth in Hastings. He said it showed his commitment to keep promises - but many mocked the "risible" stunt and said it would be the "tombstone" for Labour's election hopes. 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Paul McErlane/Getty Images General election 2015: The worst gaffes and controversies 26 April: The Ed and Boris bust-up In what was widely hailed as the best bit of election TV so far, Ed Miliband and Boris Johnson clashed head-to-head in angry scenes live on the Andrew Marr Show, forcing their usually genial host to intervene and tell the pair of them to "shut up". The increasingly animated London Mayor repeated personal attacks over Mr Miliband 'stabbing his brother in the back', while the Labour leader got in some jibes of his own about Mr Johnson's Eton education. Reuters General election 2015: The worst gaffes and controversies 25 April: Political football David Cameron’s football-loving credentials received a kicking at a campaign event in Croydon after he suggested to the audience he supported West Ham- despite previously claiming he was a huge Aston Villa fan. 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Getty Images General election 2015: The worst gaffes and controversies 21 April: Wikipedia edits Tory party chairman Grant Shapps was accused of editing the Wikipedia pages of his Conservative rivals and allegedly changing his own page to delete embarrassing references to his past. A Wikipedia administrator reported and suspended an account called 'Contribsx' on suspicion it was being used by Mr Shapps or 'someone acting on his behalf'. Getty Images General election 2015: The worst gaffes and controversies 20 April: Dodgy Tory donors? The Conservatives were forced to return more than £50,000 in donations from a businesswoman whose husband was convicted of tax fraud in the US. Beatrice Tollman, who donated £20,000 as recently as early April, was herself charged with conspiracy to evade millions of dollars’ worth of tax in the US, charges that were dismissed by a judge in 2008 General election 2015: The worst gaffes and controversies 19 April: Miliband a hit among the hens Ed Miliband was described as "the stripper" by a group of women on a hen party in Chester after they spotted the parked-up Labour battle bus. But not everyone saw it as statesmanlike behaviour, some saying it was 'cringe-worthy' and others reporting he looked 'absolutely terrified' YouTube/Chester Chronicle General election 2015: The worst gaffes and controversies 18 April: DUP on gay marriage A right-wing Democratic Unionist Party of Northern Ireland politician thanked Nick Clegg for 'reminding' voters that they are seeking to abolish same-sex marriage. 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PA General election 2015: The worst gaffes and controversies 2 April: Nigel Farage on HIV UKIP leader Nigel Farage sparked controversy during the ITV Leader's Debate 2015 for saying that immigrants who were HIV positive should not be able to enter the country and use the NHS for free. Ken McKay/ITV via Getty Images General election 2015: The worst gaffes and controversies 29 March: Labour mugs Senior Labour MP Diane Abbott was among those who led a backlash against a mug being sold by the party celebrating its new commitment to a tough immigration system. General election 2015: The worst gaffes and controversies 23 March: Ukip's Atkinson expelled Janice Atkinson, an MEP and once one of Ukip's most senior figures, was expelled after she was found to have brought the party into disrepute. Ms Atkinson’s chief of staff was secretly recorded appearing to ask the manager of a restaurant in Margate to more than treble the £950 cost of a meal before Ukip’s spring conference. Nigel Farage later said the claims 'couldn't look worse'. Chris Radburn/PA Wire General election 2015: The worst gaffes and controversies 8 January: 'Meet the Ukippers' Ukip councillor Rozanne Duncan was expelled from the party for saying she had a problem with black people because there was 'something about their faces' during filming for the BBC documentary 'Meet the Ukippers' BBC General election 2015: The worst gaffes and controversies 20 November: Emily Thornberry and the white van Labour front bench MP Emily Thornberry was forced to resign after tweeted a photo of a house in Rochester adorned with three England flags and a white van out the front, which saw her accused of holding working class voters in 'contempt'. PA General election 2015: The worst gaffes and controversies 22 October: Ukip Calypso The former BBC Radio 1 DJ Mike Read was forced to apologise for "unintentionally causing offence" with his song Ukip Calypso and asked his record company to withdraw it. 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It wasn't enough to see her disowned by the party - that came later when she was caught in a newspaper sting relating to expenses Facebook/Maria Pizzey General election 2015: The worst gaffes and controversies 16 May (2014): Nigel Farage on LBC Nigel Farage's car-crash performance on LBC was one of his worst in recent years, and culminated in him saying he would be 'uncomfortable' with a Romanian family moving in next door. The gaffe later saw Ukip take out a full-page newspaper advert insisting it was not a racist party. General election 2015: The worst gaffes and controversies 20 March (2014): 'Patronising' Grant Shapps Grant Shapps, the Conservative chairman, came under pressure from across the political spectrum after a 'patronising' tweet in which he suggested Budget measures to halve bingo tax and cut the price of beer by 1p would 'help hardworking people do more of the things they enjoy' Getty

Campbell Robb, the chief executive of the homelessness charity Shelter, called for extra funding “to pay for emergency rented accommodation so that homeless families aren’t forced miles away from all they know.

“Uprooting homeless families and sending them away from their jobs, schools and support networks should only ever be a last resort, but shockingly it’s now the norm in London,” he added.

Mr Robb said the issue was a symptom of a housing crisis brought about by the lack of affordable homes. Research by estate agents Savills found that London needs around 50,000 new homes a year to keep up with demand, with a third needing to be at social or “affordable” rent levels.

Meanwhile, a spokesperson for Southwark council called on more external help: “Central government and the Greater London Authority need to recognise the London explosion of homelessness and help councils address the record numbers we are now dealing with.”

A protester holds a sign at the 'March for Homes' rally outside City Hall in London earlier this year (Getty Images)

Leading housing lawyers said more transparency over out-of-borough placements was needed so councils could be held to account. Government guidance requires that councils house families inside their borough “so far as reasonably practicable”. A recent Supreme Court decision ruled that councils could not place families a distance from their borough without providing evidence of having searched for closer accommodation.

Jayesh Kunwardia, a partner at Hodge, Jones & Allen, who took an out-of-borough placement case to the Supreme Court, said: “The law is clear but councils aren’t following it in a huge number of instances. We need greater transparency and less secrecy.”

A Green Party spokesperson said: “The casual indifference of this Government and Mayor betrays a horrific lack of care towards people.”

Karen Buck, who was the Labour MP for Westminster North, warned that the exodus of poor families was a danger to the prosperity of the city: “Cities have to be mixed, not just for social and moral reasons, but because someone needs to do the low-paid jobs.”