More than half a million social homes in England fail to meet basic health and safety standards, an analysis of official government data by The Independent has revealed.

Just weeks after the Grenfell Tower fire raised serious questions about the state of housing in the UK, new statistics show that 525,000 social homes currently do not meet the national Decent Homes Standard – almost one in seven of all social homes in England.

Of these, 244,000 properties are deemed to have a category one safety hazard – the highest category of risk — which includes potentially fatal hazards such as exposed wiring, overloaded electricity sockets, dangerous boilers, leaking roofs, vermin infestations or inadequate security.

Local authorities have a legal duty to act if a category one hazard is discovered, but hundreds of thousands are going unreported or ignored.

In total, it means more than a million people are likely to be living in social homes that fail the Government’s own minimum benchmark for human habitation. Millions more are suffering the same fate in properties rented from private landlords.

The proportion of social homes that are sub-standard has barely fallen in recent years, as austerity policies mean government funding for housing improvements has dried up.

The new data comes from the government-commissioned English Housing Survey, which is published once a year and provides a snapshot of the state of housing.

It is likely to renew pressure on government ministers, local councils and housing associations to take action to improve the quality of social housing, especially in the wake of the Grenfell Tower disaster.

As urgent testing of building cladding and insulation is conducted by the Government and local authorities, The Independent’s analysis raises broader questions about the safety of social homes – even in properties where building regulations have been met and the correct materials used.

Particularly worrying after the Grenfell Tower fire, the number of homes in high-rise tower blocks that contain category one hazards has increased since 2013.

One in seven homes in purpose-built tower blocks currently fail the Government’s own benchmark for adequate housing.

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Properties classed as “non-decent” must have failed on one or more measures: they either did not meet basic safety standards; are considered to be in state of disrepair; do not have modern bathroom and sanitation facilities, or lack adequate heating.

Last year, the biggest reason for social homes being classed as substandard was because they had a category one health and safety hazard. 244,000 homes were in this category – more than half of the social homes in England deemed to be inadequate.

The Decent Homes Standard is just one measure of the quality of social housing. A property could have a host of other problems while not necessarily failing to meet the benchmark.

Four criteria are used to assess whether a property is classed as being in “poor condition”, of which the Decent Homes Standard is just one, and the category one hazard test another. The two other tests relate to disrepair and damp.

In England, 364,000 social homes are classed as being in a state of “substantial disrepair”, while 205,000 have damp in one or more rooms.

Shockingly, 89,000 social homes failed on either three or four of the four measures of poor-quality housing.

Grenfell Tower fire: A timeline of the tragedy

The proportion of social homes classed as non-decent has barely changed in the last five years, with hundreds of thousands of families stuck in non-decent homes as government funding streams for improvements have dried up.

Between 2001 and 2010, as part of a huge programme of investment, an estimated £37bn was spent on improving social homes, of which at least £22bn was provided by the Department for Communities and Local Government (DCLG) via the Decent Homes Programme, established in 2001.

As a result, the number of social homes classed as non-decent fell by more than a million – from 39 per cent of all social homes in 2001, to 15 per cent in 2012.

In contrast, funding has been scarce since 2011. The Coalition government committed just £1.6bn to the Decent Homes Programme between 2011 and 2015, and the Government has now stopped funding the programme entirely.

The proportion of social homes classed as non-decent fell by just two per cent from 2012 to 2016: from 15 per cent to 13 per cent.

The Government now says councils “should have the resources to keep all their social housing at a decent level” without central funding.

But Labour said it was “shameful” that ministers have stopped funding the Decent Homes Programme when so many properties remain in a sub-standard condition.

In Pictures: Grenfell Tower after the fire Show all 51 1 /51 In Pictures: Grenfell Tower after the fire In Pictures: Grenfell Tower after the fire Police have released images from inside the tower where at least 58 people have died Metropolitan Police In Pictures: Grenfell Tower after the fire A still from a video shared by polices what appears to be a stationary bicycle sitting among the ashes In Pictures: Grenfell Tower after the fire A still from a video shared by police shows the remnants of a burnt-out bathroom In Pictures: Grenfell Tower after the fire Picture showing the lifts on an unknown floor Metropolitan Police In Pictures: Grenfell Tower after the fire Emergency crews outside the front entrance to the tower Metropolitan Police In Pictures: Grenfell Tower after the fire Fire crews inspecting flats in the burnt out tower London Metropolitan Police In Pictures: Grenfell Tower after the fire Grenfell Tower is seen in the distance PA In Pictures: Grenfell Tower after the fire A drone flies near the scene of the fire which destroyed the Grenfell Tower block REUTERS/Stefan Wermuth In Pictures: Grenfell Tower after the fire 'Theresa May Stay Away' message written on the messages of support at Latymer Community Church for those affected by the fire Ray Tang/REX In Pictures: Grenfell Tower after the fire An aerial view of the area surrounding Grenfall tower Getty In Pictures: Grenfell Tower after the fire Donated shoes sit in the Westway Sports Centre near to the site of the Grenfell Tower fire Getty Images In Pictures: Grenfell Tower after the fire Messages of support for those affected by the massive fire in Grenfell Tower are displayed on a well near the tower in London AP In Pictures: Grenfell Tower after the fire A local resident stands on her balcony by the gutted Grenfell Tower in Latimer Road Getty Images In Pictures: Grenfell Tower after the fire Messages of condolence are left at a relief centre close to the scene of the fire that broke out at Grenfell Tower, EPA In Pictures: Grenfell Tower after the fire A police officer stands by a security cordon outside Latimer Road station Getty Images In Pictures: Grenfell Tower after the fire Firemen examine the scorched facade of the Grenfell Tower in London on a huge ladder AP In Pictures: Grenfell Tower after the fire A search dog is led through the rubble of the Grenfell Tower in London as firefighting continue to damp-down the deadly fire AP In Pictures: Grenfell Tower after the fire Labour leader Jeremy Corbyn comforts a local resident (name not given) at St Clement's Church in west London where volunteers have provided shelter and support for people affected by the fire at Grenfell Tower David Mirzoeff/PA In Pictures: Grenfell Tower after the fire Labour leader Jeremy Corbyn hugs councillor Mushtaq Lasharie as he arrives at St Clement's Church in Latimer Road, where volunteers have provided shelter and support for people affected by the fire at Grenfell Tower Getty Images In Pictures: Grenfell Tower after the fire Labour leader Jeremy Corbyn meeting staff and volunteers at St Clementís Church in Latimer Road David Mirzoeff/PA In Pictures: Grenfell Tower after the fire Firefighters with a dog walk around the base of the Grenfell Tower REUTERS/Peter Nicholls In Pictures: Grenfell Tower after the fire Emotions run high as people attend a candle lit vigil outside Notting Hill Methodist Church near the 24 storey residential Grenfell Tower block in Latimer Road, West London Getty Images In Pictures: Grenfell Tower after the fire Debris hangs from the blackened exterior of Grenfell Tower Getty Images In Pictures: Grenfell Tower after the fire A woman speaks to Mayor of London Sadiq Khan outside Notting Hill Methodist Church near Grenfell Tower in west London after a fire engulfed the 24-storey building Yui Mok/PA Wire In Pictures: Grenfell Tower after the fire A woman holds a missing person posters near the Grenfell Tower block REUTERS/Stefan Wermuth In Pictures: Grenfell Tower after the fire Sadiq Khan speaking with a resident James Gourley/REX In Pictures: Grenfell Tower after the fire Ken Livingstone walks near the scene of the Grenfell Tower fire Getty Images In Pictures: Grenfell Tower after the fire Mayor of London Sadiq Khan is confronted by Kai Ramos, 7, near Grenfell Tower in west London after a fire engulfed the 24-storey building Yui Mok/PA Wire In Pictures: Grenfell Tower after the fire Mayor of London Sadiq Khan speaks to a woman outside Notting Hill Methodist Church near Grenfell Tower Yui Mok/PA Wire In Pictures: Grenfell Tower after the fire Volunteers distribute aid near Grenfell Tower Getty Images In Pictures: Grenfell Tower after the fire Family and friends of missing Jessica Urbano, 12, wearing photographs of Jessica pinned to their t-shirts gather near Grenfell Tower EPA In Pictures: Grenfell Tower after the fire Family and friends of missing Jessica Urbano, 12, wearing photographs of Jessica pinned to their t-shirts gather near Grenfell Tower EPA In Pictures: Grenfell Tower after the fire Family and friends of missing Jessica Urbano, 12, wearing photographs of Jessica pinned to their t-shirts gather near Grenfell Tower EPA In Pictures: Grenfell Tower after the fire People attend a vigil at Notting Hill Methodist Church near Grenfell Tower Getty Images In Pictures: Grenfell Tower after the fire People gather to observe a vigil outside St Clement's Church following the blaze at Grenfell Tower Getty Images In Pictures: Grenfell Tower after the fire People light candles as they observe a vigil outside St Clement's Church following the blaze at Grenfell Tower Getty Images In Pictures: Grenfell Tower after the fire People attend a vigil at Notting Hill Methodist Church near Grenfell Tower Getty Images In Pictures: Grenfell Tower after the fire A man distributes food from the back of a van near the scene of the fire which destroyed the Grenfell Tower block REUTERS/Paul Hackett In Pictures: Grenfell Tower after the fire A firefighter is cheered near the scene of the fire which destroyed the Grenfell Tower block REUTERS/Paul Hackett In Pictures: Grenfell Tower after the fire A T-shirt with a written message from the London Fire Brigade hangs from a fence near The Grenfell Tower block REUTERS/Stefan Wermuth In Pictures: Grenfell Tower after the fire A young girl on her way to lay flowers near Grenfell Tower Getty Images In Pictures: Grenfell Tower after the fire The remains of residential tower block Grenfell Tower are seen from Dixon House a nearby tower block Getty In Pictures: Grenfell Tower after the fire Volunteers prepare supplies for people affected by the Grenfell Tower block which was destroyed in a fire REUTERS/Neil Hall In Pictures: Grenfell Tower after the fire Volunteers move a car to make space for a lorry picking up supplies for people affected by the Grenfell Tower block REUTERS/Stefan Wermuth In Pictures: Grenfell Tower after the fire People distribute boxes of food near the scene of the fire which destroyed the Grenfell Tower bloc REUTERS/Paul Hackett In Pictures: Grenfell Tower after the fire A woman touches a missing poster for 12-year-old Jessica Urbano on a tribute wall after laying flowers on the side of Latymer Community Church next to the fire-gutted Grenfell Tower AP In Pictures: Grenfell Tower after the fire A man looks at messages written on a wall near the scene of the fire which destroyed the Grenfell Tower block REUTERS/Paul Hackett In Pictures: Grenfell Tower after the fire Candles and messages of condolence near where the fire broke out at Grenfell Tower EPA In Pictures: Grenfell Tower after the fire Police carry a stretcher towards Grenfell Tower Rick Findler/PA Wire In Pictures: Grenfell Tower after the fire Emergency services at Grenfell Tower Rick Findler/PA Wire In Pictures: Grenfell Tower after the fire Police carry out a body from Grenfell Tower in west London after a fire engulfed the 24-storey building Rick Findler/PA Wire

John Healey, the party’s Shadow Housing Secretary, told The Independent: “When over half a million social homes can’t be classed as decent, it’s shameful that ministers have axed all funding for the Decent Homes Programme to upgrade social housing. Under Labour, we invested more than £22bn to bring more than a million social homes up to scratch.

“Since 2010, Conservative ministers have washed their hands of any responsibility for decent conditions in social housing, and with new affordable house-building now at a 24-year low, they’re also failing to build the homes families on ordinary incomes need.

“After seven years of failure, the Conservatives have no plan to fix the housing crisis. A Labour government would restart the Decent Homes Programme and invest to build the new genuinely affordable homes that the country needs.”

The new statistics reveal that, in addition to sub-standard properties, 258,000 families are living in social homes classed as overcrowded; 217,000 of those families include children.

Anne Baxendale, director of campaigns and policy at Shelter, said: “Shelter’s own research has shown that three out of 10 households living in social housing are not happy with the condition of their home, and although standards are gradually improving, progress seems to have stalled.

“Sadly, too many tenants’ complaints are not dealt with quickly, efficiently, or sometimes even at all.

“Everyone, no matter where they live, deserves to have somewhere safe, decent and affordable to call home. Despite less funding, it’s essential that councils and housing associations listen to tenants’ concerns and are committed to ensuring no one is forced to tolerate an unsafe home.”

A DCLG spokesman said: "The health and safety of those living in social housing is paramount – that’s why social landlords are obliged by law to maintain their properties to a good standard. Government action has seen the number of homes failing to meet the Decent Homes Standard continue to fall with 24 per cent less non-decent homes than last year, and more than a million sub-standard properties brought up to standard since 2010.