- Video report by ITV News Business Editor Joel Hills
Grenfell Tower recently underwent a £9 million upgrade which was inspected and signed off by Kensington and Chelsea council.
The work was carried out by Rydon, a company which constructs and maintains buildings in London and the south-east.
The company said the work it carried out met "all required building control, fire regulation, and health and safety standards".
While many people who witnessed the blaze have suggested that the cladding on the outside of the building may have played a role in spreading the fire quickly, Andrew Goldman, Rydon's Technology Director, said at the current stage of the investigation there is no "direct link between the fire and the cladding".
Mr Goldman continued that the cause of the blaze is still not known.
While the refurbishment was carried out by Rydon, another company, Harley Facades Limited, clad the block's exterior and replaced the windows but did not manufacture them.
Grenfell Tower block is managed by the Kensington and Chelsea Tenant Management Organisation, which London Fire Brigade previously took enforcement action against after a fire at another block it managed, finding a list of failures.
In the aftermath all the companies have pledged to do what they can to aid the investigation.