Councils across London may be risking the lives of thousands of residents - because hundreds of tower blocks have not been assessed for fire safety.
A BBC London investigation has found at least 300 social housing high-rises have no valid fire check from their local authority - a criminal offence.
Lambeth Council, the worst offender, has only carried out risk assessments on two of its 112 tower blocks.
An expert who visited one block branded it a "disaster waiting to happen".
In July six people died during a fire at Lakanal House, a 12-storey block in Southwark now thought to have been unsafe.
But the research suggests the problem of unsafe tower blocks could be widespread.
It's just appalling that this block has never had a fire risk assessment - Lambeth is seriously lacking
Arnold Tarling, fire surveyor
Under the Regulatory Reform Fire Safety Order 2005, councils are compelled to conduct fire risk assessments before and during major refurbishments.
Freedom of Information requests sent to 32 boroughs showed at least eight councils have been failing to do this.
In many cases a fire risk assessment had not been carried out in the first place.
The responses from councils revealed there are 72 unchecked and potentially unsafe tower bocks in Greenwich, 63 in Westminster and 34 in Hammersmith and Fulham.
BBC London asked Arnold Tarling, a chartered surveyor with 22 years' experience in fire risk, to visit Brittany Point, a block in Lambeth which has never been fire assessed.
Mr Tarling, who called the block a "disaster waiting to happen", found a catalogue of fire hazards, including:
Flammable expanding foam around windows which would give off a thick black smoke if set alight.
A 13-year gap in recorded fire hose services.
Gaps underneath fire-resistant panels, which would render them useless.
Panels containing a polystyrene which could melt, give off smoke and add fuel to flames.
He said: "Those polystyrene panels are one of the causes of [the rapid spread of fire at] Lakanal House.
"Flats in tower blocks are supposed to have an hour's fire resistance.
"At Brittany Point they don't even have 10 minutes - I would say it's zero."
Foam from Brittany Point's windows burns and gives off toxic smoke
He continued: "It's just appalling that this block has never had a fire risk assessment - Lambeth is seriously lacking."
Mr Tarling, who has appeared as an expert witness in court cases, said of the London-wide picture: "Unfortunately it doesn't surprise me at all.
"I have been warning about this for 20 years."
Mr Tarling warned the bad practice was probably replicated across the UK.
A Lambeth Council spokesman said: "Lambeth Council's housing stock is larger than most other boroughs, and by December all blocks over 10 storeys will hold a valid fire safety risk assessment, with the remaining high rise blocks being completed by March 2010."
Kurt Barling, BBC London Special Correspondent
Southwark Council seems to want as few people to talk about the Lakanal House disaster as possible. We took a reputable surveyor to one block. His assessment was that the work to make the building and flats look nicer is actually increasing the risk of fire spreading. How can this not be a scandal? The lessons from Lakanal cannot wait until police investigations are completed, nor until inquests are held. Our investigations show there are serious systemic shortcomings in complying with regulations. A third of London's boroughs have an up-to-date fire assessment record. It is possible to get the work done. Surely the law becomes an ass if it is consistently ignored?
Since BBC London began inquiring about fire risk assessments several councils, including Barnet and Barking and Dagenham, have carried out urgent programmes to assess all their tower blocks, beginning with the tallest.
Southwark Council, which controls Lakanal House, refused to answer the BBC's Freedom of Information request.
The council has already had enforcement orders placed on it by London Fire Brigade because of its attitude to fire safety.
And as BBC London revealed in July, weeks after the fatal fire at Lakanal House, the council had known the block was a fire risk for almost a decade - but had done nothing.
Lakanal House did not have a valid fire risk assessment in place when fire broke out.
A Southwark Council spokesman said revealing the number of its tower blocks without valid risk assessments would "prejudice" the official investigation into the Lakanal fire.
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