Lives could be put at risk by shoddy work to remove highly-flammable cladding from tower blocks in the wake of the Grenfell Tower disaster, ministers have been warned.

Contractors have left some high-rise blocks even more unsafe than when they began removing the cladding, experts said, with some buildings still flouting fire regulations, while the most extreme cases revealed "serious structural issues" after repairs.

Housing minister Dominic Raab is set to be grilled by MPs on Monday over what emerged as a fresh hurdle in the government’s drive to make tower blocks safe.

The Independent reported earlier this week how the number of private tower blocks covered in the flammable material is twice as high as previously thought.

Claire Curtis-Thomas, chief executive officer of the British Board of Agrement (BBA), the industry's certification body, told MPs that contractors doing repairs were either "suffering with rank ignorance" or complicit in doing a bad job, after her team discovered 30 tower blocks were still unsafe after the cladding was removed.

She told the Housing, Communities and Local Government Committee (CLG) that companies were being "silenced" by the potential cost of repairs, which could run to millions if remedial work has to be re-done.

The findings open up a new front in the battle to improve the safety of high-rise buildings after Grenfell Tower, where flammable cladding was blamed for the rapid spread of the blaze through the west London tower block.

Labour committee chairman, Clive Betts, warned that poorly-done work could cost lives, as well as racking up major bills for the government if further repairs need to be made.

Mr Betts told The Independent: “If there are 30 that are wrong - if it was the odd one you might think an individual has made a failure - but again it’s about having people who are not completely qualified or don’t completely understand everything doing the job.

"I think there is a wider implication. The construction industry is not fit for purpose if it's got products which shouldn't be on buildings, it's installed in a way that shouldn't be installed, it's got people who are not competent and jobs that are done where no one seems accountable at the end of the day."

He has written to housing secretary James Brokenshire over the news and vowed to get answers from the housing minister Dominic Raab when he appears before MPs on Monday.

Mr Betts added: "Two things need to happen. There's clear a significant cost that the government's going to have pay for.

"And somebody needs to be held accountable for this. It's not this, 'Oh we got it wrong, let's put it right'. We got it so badly wrong that people have to be held properly accountable.

"This is not just a mistake that cost money, it's a mistake that could have cost people's lives - or could cost people's lives unless it is corrected."

The figures emerged during a committee hearing this week, where Ms Curtis-Thomas told MPs that a team of specialists had found that 30 of the 32 buildings they examined had been left in an unsafe state.

The team found that the “substrate” - which supports the cladding - was not compliant with fire-safety regulations in many cases, while two buildings had “serious structural issues”.

Ms Curtis-Thomas said: “You can have non-combustible materials but if you have poor installation of that productyou could still have the situation we have seen in Grenfell.”

She went on: “The people that are carrying out the remediation work are either completely ignoring what they’re seeing below the cladding that they’re actually removing or they don’t understand what they’re looking at.

“The lack of competence on the ground to determine whether the job has been done properly is woeful and secondly, the people who are designing these systems, either are complicit in doing a bad job or actually they’re also suffering with rank ignorance.”

Ministers should either order remedial works or start the repairs from scratch to prevent further risks, both of which will rack up a major cost, Ms Curtis-Thomas said.

“Just re-cladding the building might cost you £1m. If you start to look at remediation this starts to look like a £2 or £3m job," she said.

“So the cost of doing the work, I think, silences quite a number of organisations.”

The BBA has written to the government to express their fears that guidance was not being understood or followed, and demanded an audit of work that have already been done.

In Pictures: Grenfell Tower after the fire







51 show all In Pictures: Grenfell Tower after the fire



































































































1/51 Police have released images from inside the tower where at least 58 people have died Metropolitan Police

2/51 A still from a video shared by polices what appears to be a stationary bicycle sitting among the ashes

3/51 A still from a video shared by police shows the remnants of a burnt-out bathroom

4/51 Picture showing the lifts on an unknown floor Metropolitan Police

5/51 Emergency crews outside the front entrance to the tower Metropolitan Police

6/51 Fire crews inspecting flats in the burnt out tower London Metropolitan Police

7/51 Grenfell Tower is seen in the distance PA

8/51 A drone flies near the scene of the fire which destroyed the Grenfell Tower block REUTERS/Stefan Wermuth

9/51 'Theresa May Stay Away' message written on the messages of support at Latymer Community Church for those affected by the fire Ray Tang/REX

10/51 An aerial view of the area surrounding Grenfall tower Getty

11/51 Donated shoes sit in the Westway Sports Centre near to the site of the Grenfell Tower fire Getty Images

12/51 Messages of support for those affected by the massive fire in Grenfell Tower are displayed on a well near the tower in London AP

13/51 A local resident stands on her balcony by the gutted Grenfell Tower in Latimer Road Getty Images

14/51 Messages of condolence are left at a relief centre close to the scene of the fire that broke out at Grenfell Tower, EPA

15/51 A police officer stands by a security cordon outside Latimer Road station Getty Images

16/51 Firemen examine the scorched facade of the Grenfell Tower in London on a huge ladder AP

17/51 A search dog is led through the rubble of the Grenfell Tower in London as firefighting continue to damp-down the deadly fire AP

18/51 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

19/51 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

20/51 Labour leader Jeremy Corbyn meeting staff and volunteers at St Clementís Church in Latimer Road David Mirzoeff/PA

21/51 Firefighters with a dog walk around the base of the Grenfell Tower REUTERS/Peter Nicholls

22/51 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

23/51 Debris hangs from the blackened exterior of Grenfell Tower Getty Images

24/51 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

25/51 A woman holds a missing person posters near the Grenfell Tower block REUTERS/Stefan Wermuth

26/51 Sadiq Khan speaking with a resident James Gourley/REX

27/51 Ken Livingstone walks near the scene of the Grenfell Tower fire Getty Images

28/51 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

29/51 Mayor of London Sadiq Khan speaks to a woman outside Notting Hill Methodist Church near Grenfell Tower Yui Mok/PA Wire

30/51 Volunteers distribute aid near Grenfell Tower Getty Images

31/51 Family and friends of missing Jessica Urbano, 12, wearing photographs of Jessica pinned to their t-shirts gather near Grenfell Tower EPA

32/51 Family and friends of missing Jessica Urbano, 12, wearing photographs of Jessica pinned to their t-shirts gather near Grenfell Tower EPA

33/51 Family and friends of missing Jessica Urbano, 12, wearing photographs of Jessica pinned to their t-shirts gather near Grenfell Tower EPA

34/51 People attend a vigil at Notting Hill Methodist Church near Grenfell Tower Getty Images

35/51 People gather to observe a vigil outside St Clement's Church following the blaze at Grenfell Tower Getty Images

36/51 People light candles as they observe a vigil outside St Clement's Church following the blaze at Grenfell Tower Getty Images

37/51 People attend a vigil at Notting Hill Methodist Church near Grenfell Tower Getty Images

38/51 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

39/51 A firefighter is cheered near the scene of the fire which destroyed the Grenfell Tower block REUTERS/Paul Hackett

40/51 A T-shirt with a written message from the London Fire Brigade hangs from a fence near The Grenfell Tower block REUTERS/Stefan Wermuth

41/51 A young girl on her way to lay flowers near Grenfell Tower Getty Images

42/51 The remains of residential tower block Grenfell Tower are seen from Dixon House a nearby tower block Getty

43/51 Volunteers prepare supplies for people affected by the Grenfell Tower block which was destroyed in a fire REUTERS/Neil Hall

44/51 Volunteers move a car to make space for a lorry picking up supplies for people affected by the Grenfell Tower block REUTERS/Stefan Wermuth

45/51 People distribute boxes of food near the scene of the fire which destroyed the Grenfell Tower bloc REUTERS/Paul Hackett

46/51 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

47/51 A man looks at messages written on a wall near the scene of the fire which destroyed the Grenfell Tower block REUTERS/Paul Hackett

48/51 Candles and messages of condolence near where the fire broke out at Grenfell Tower EPA

49/51 Police carry a stretcher towards Grenfell Tower Rick Findler/PA Wire

50/51 Emergency services at Grenfell Tower Rick Findler/PA Wire

51/51 Police carry out a body from Grenfell Tower in west London after a fire engulfed the 24-storey building Rick Findler/PA Wire

Sir Ken Knight, who chairs the independent expert panel on building safety, told MPs: “That would cause me real concern, because the expert panel has issued clear advice via DCLG [Ministry of Housing, Communities and Local Government] to both building owners and building authorities, that it isn't just replacing cladding, it’s about the system behind it, the intumescent strips, the separation of the gaps.

“We have never said it’s just about cladding, we have said the building system needs to be looked at."

The government is mulling a ban on combustible building materials, despite a long-awaited report by Dame Judith Hackitt

Theresa May vowed to spend £400 stripping dangerous cladding from public buildings however it is still unclear who will pay for privately-owned blocks, after some building owners refused to meet the costs.

Earlier, Mr Brokenshire announced a new taskforce to ensure plans to make private blocks safe “are put in place swiftly”.

However he admitted in a written statement that work has begun on just 21 of the buildings and completed on only four.

An MHCLG spokesperson said: “Nothing is more important than ensuring people are safe in their homes. Following the Grenfell Tower tragedy, we acted swiftly to establish a comprehensive testing programme, issued clear guidance to building owners and commissioned an independent review of building regulations and fire safety by Dame Judith Hackitt.