IN other parts of the country tower blocks built using the Large Panel System have been evacuated and will be demolished after inspectors found serious structural flaws.

In February, hundreds of residents in two blocks of high rise flats in Portsmouth, built using the LPS, were told they had to move out after a survey found weaknesses in the buildings’ concrete floor slabs and walls.

READ MORE: Investigation launched into city's high rise LPS blocks

READ MORE: Here are the eight tower blocks being invesitgated

A history of LPS tower blocks

The system was a popular method of building high rise flats in the 1960s and 1970s in a rush to house the population following the “baby boom” after the Second World War.

The system is essentially a method of construction in which walls, floors and ceilings, called panels, are produced in factories and put together on site.

Eight of these blocks were built in Brighton and Hove in the 1960s.

READ MORE: Investigation launched into city's high rise LPS blocks

READ MORE: Here are the eight tower blocks being invesitgated

Concerns about the construction method were raised in 1968, when an LPS building in London called Ronan Point collapsed in a gas explosion.

It happened when resident Ivy Hodge lit a match. A bad connection between the gas main and her cooker had allowed gas to leak into the kitchen.

The gas exploded, throwing her to the floor. She was knocked out and received some minor burns.

And when she came round, she found a large portion of the 22-storey high rise in which she lived had collapsed.

Mrs Hodge survived but the collapse of part of the building killed four people and injured 17.

A government minister then ordered a complete shut off of gas in all of the blocks, after tests found key joints would fail in the event of an explosion.

After a review into the tragedy, the government wrote to all local authorities to give advice about the need for an “urgent appraisal”.

Where necessary, councils were told about measures for strengthening existing blocks.

New calls for safety

In 2017 in the London Borough of Southwark, residents raised concerns about cracks in their buildings.

Structural engineers were subsequently instructed by the council to investigate the cause of the cracking.

These cracks led to inspectors being concerned about fire safety.

READ MORE: Investigation launched into city's high rise LPS blocks

READ MORE: Here are the eight tower blocks being invesitgated

In large tower blocks, residents are told to stay in their flats as fire should be contained by doors, floors and walls which act as barriers to stop smoke and flames from spreading.

Earlier this year, residents in Horatia House and Leamington House in Portsmouth, both LPS buildings, were evacuated after an inspection.

It was deemed “financially unviable” to carry out necessary refurbishment.

It was only when cladding was removed from both buildings after the Grenfell tragedy that engineers realised the original 1960s concrete construction of the blocks was not strong enough.