Police became so concerned about the safety of fourth-floor resident Behailu Kebede that they “suggested witness protection”, said his lawyer Rajiv Menon QC.
He said journalists had relentlessly pursued his client and his family following the fire, in which 72 people died.
Mr Menon said Mr Kebede suffered repercussions to his health. They were not outlined but the inquiry heard the tenant was also “terrified” at the prospect of giving evidence.
The lawyer said Mr Kebede was subject to a “nasty lie” about packing a bag before fleeing the burning building.
He said the tenant acted “quickly and instinctively” when he was awoken by his smoke alarm, calling 999 and alerting neighbours.
Mr Menon said his client, who lived in the block for 25 years, left the building with no shoes, keys or wallet – just the clothes he had on and the mobile phone he used to call emergency services.
“In short, Behailu Kebede did exactly what Grenfell Tower residents who discovered a fire in their flat were told to do by the fire action notice posted by the lifts,” the lawyer said.
“He desperately wanted to do more to help his neighbours and friends, but what more could he do? He felt utterly helpless.”
The inquiry heard Mr Kebede was concerned about refurbishment work at Grenfell and “personally had problems with incorrectly fitted double-glazed windows that left gaps between the frame and the concrete”.
It has been suspected that fire set light to exterior cladding through gaps around the flat windows.
Mr Menon said his client “had the most frightening, traumatic and shocking experience of his life” but did not hesitate to cooperate with police inquiries.
He added: “It is important to stand against all the garbage that has been written… Mr Kebede is a significant witness in the police investigation, not a criminal suspect.”
It is suspected that the fire started from a Hotpoint fridge-freezer in the flat, but the lawyer said there had been no previous issues with it and that it had not been tampered with.
Mr Menon called on inquiry chairman Sir Martin Moore-Bick to “explicitly exonerate” Mr Kebede from “sleazy accusations and hurtful innuendo” aimed at him.
“Sitting on the fence in respect of Mr Kebede, with the greatest respect, will not do,” he added.
Among those giving evidence at the inquiry on Wednesday was fire risk assessor CS Stokes, which said in its opening statement that the tower’s safety measures were not designed to withstand a fire of such intensity.
The safety assessor, after a 2014 assessment while refurbishment was under way, highlighted the block as a “high priority” risk and in need of a resolution as the “cladding affixed to the external wall at the moment is on timber battens”.
As the inquiry continues, banners have been unfurled at the top of Grenfell Tower with the words: “Forever in our hearts.”
It comes in preparation of the one-year anniversary of the tragedy on 14 June. It is understood banners will appear on all four sides of the tower, covering the top four floors.
Some residents previously voiced concern over the move, saying the building should remain completely uncovered as a reminder of the fire.
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The Grenfell site management team said: “We have worked with representatives of the bereaved and survivors from Grenfell tower to develop appropriate remembrance for the forthcoming one year commemorations.
“The first of the banners has been installed today and the others will be installed in the days leading up to the 14 June to mark one year since the fire.”