Companies that made the cladding and insulation used on Grenfell Tower will be questioned this week as an inquiry seeks to establish where responsibility lies for the fire that killed 72 people.

The 2017 fire at the London tower block and the inquiry that followed have raised serious doubts about the safety of high-rise buildings, the companies that built and clad them and the regulatory regime in which they operated.

With mortgage lenders fearful of the risk of financing the purchase of potentially unsafe flats, as many as 11m people in England face being trapped in properties they are unable to sell.

Meanwhile, a fierce debate is raging in Westminster and the construction industry about who should foot the bill for repairing potentially unsafe buildings.

Rishi Sunak, the chancellor, is meeting communities secretary Robert Jenrick this week to finalise the details of a new funding package worth billions of pounds that could be announced as early as the following week.

Last week the head of one of the UK’s largest housebuilders called for a levy on developers to help cover costs, which — according to some experts — could run as high as £15bn.

“We believe that housebuilders and the broader industry have a collective responsibility to be a part of the solution,” said David Thomas, chief executive of Barratt Developments.

Some Tory MPs have, meanwhile, expressed concerns that the Treasury assistance could take the form of loans — equivalent to a second mortgage — that leaseholders would have to pay back.

The Grenfell inquiry resumes on Monday, having been halted on December 9 owing to Covid-19, with two of the world’s largest manufacturers of cladding and insulation set to face scrutiny.

This week the inquiry will hear from employees of Kingspan, the Irish insulation giant, and Arconic, an American cladding manufacturer that, through a French subsidiary, sold the aluminium composite material panels used on Grenfell. Similar ACM panels are being stripped from high-rise buildings across England as part of efforts to remediate at-risk towers.

The following week will be dedicated to evidence from Claude Schmidt, the president of the French arm of Arconic. Despite heading the company that supplied the panelling identified as the main cause of the fire’s spread, Schmidt has so far not attended the inquiry, citing an arcane French law banning disclosure to foreign courts.

A number of Schmidt’s former colleagues will not be attending, including Claude Wehrle, a former member of Arconic’s technical team who appeared to flag the potential dangers of ACM cladding in a 2009 email to Schmidt seen by the inquiry.

Edward Daffarn, a survivor of the fire, welcomed Schmidt’s attendance but said “we really need all of them to come”, adding that he was disappointed that the companies had not shown more “remorse or contrition”.

The resumption of the inquiry will ratchet up the pressure on the companies. In early November, the inquiry heard claims that Kingspan had abused the fire safety testing regime to pass off its product as safe. Shares in the company have tumbled 30 per cent since then.

Kingspan’s representative at the inquiry, Geraint Webb, offered a “full apology” for what he described as “shortcomings” in the company’s testing procedures. But, he added, those “shortcomings did not impact the safety of any cladding system incorporating K15 [the Kingspan product used on Grenfell]”.

With Arconic witnesses set to take the stand, “there may be some similar revelations about the company as we had with Kingspan”, said Ritu Saha, a spokesperson for the campaign group UK Cladding Action Group.

“But the question is what will it lead to? It’s been more than three-and-a-half years and none of these firms have faced any penalties . . . 72 people died and years later not one person has been prosecuted,” she added.

Arconic said it “continues to fully co-operate with the authorities and the inquiry at all times”.