Media playback is unsupported on your device Media caption Metropolitan Police footage shows investigators entering the smoke-blackened staircases

Fire service advice to "stay put" inside Grenfell Tower during the fire which destroyed the building lasted nearly two hours, the BBC has learned.

A change in policy recommending residents try to leave was made at 02:47 BST, one hour and 53 minutes after the first emergency call.

At least 80 people are believed to be dead after the blaze on 14 June.

London Fire Brigade said: "The advice our control officers give can change as the fire changes."

Meanwhile, tributes have been laid at a wall in the tower's North Kensington neighbourhood to mark the four weeks since the blaze occurred.

When the fire was first reported at 00:54 BST, residents were initially given advice to "stay put" inside the building.

This is based on the assumption that fire can be contained, but the policy has come under scrutiny after many of the tower's residents became trapped.

Image copyright PA Image caption Tributes are being paid to mark the four-week anniversary of the fire

Image copyright AFP/Natalie Oxford

Karim Musillhy spoke to his uncle Hesham Rahman, 57, on the phone at 01.30 BST.

He says the emergency services had told him to stay in his flat and put wet towels under the door.

"We all know how it all caught fire very quickly. But even then, for me I would be thinking, 'if you can make it out, make it out. Just get out of the building. Get out.'

"Within 15 minutes, the whole building caught fire. After two hours, it's too late."

'Arrest someone'

Image copyright PA

Met Police officer Matt Bonner, who is leading the investigation into the fire, was confronted by angry people during a meeting on Wednesday evening at St Clement's Church, a short distance from Grenfell Tower.

Mr Bonner told those gathered he could not discuss the investigation "as it would put the investigation at risk", but this led to cries of "arrest someone" from those gathered.

He also said the police investigation would "not be quick but it would be thorough".

Hilary Patel, from the Grenfell Response Team, also said the building "has never been at risk of falling down".

And Dr Deborah Turbitt, from Public Health England, said the area had been monitored for traces of asbestos, but none had been found.

Elsewhere in the neighbourhood, not far from the church, hundreds of people slowly gathered at a wall covered with tributes, to pay respects to those who died four weeks ago. Many were in tears.

The evening vigil saw pictures, flowers and handwritten messages illuminated by candles left by those paying their respects.

Nabil Choucair fears he has lost six members of his family who lived on the 22nd floor of Grenfell Tower.

He says the stay put policy may have been maintained for too long.

"You take away their only chance of probably escaping. I heard of firemen making it up to the 21st, 22nd [floor] and rescuing people, but choosing who to save, and who not to save because they couldn't carry any more, or help anyone.

"After that time, the chances have dropped for them and for everybody else."

Image copyright EPA

Paul Embery of the Fire Brigades Union said the stay put advice is "broadly sound".

"Clearly this was an unprecedented fire, and people couldn't have foreseen the way the fire was going to spread.

"At some point it was obvious that the advice needed to change. Whether it should have been changed earlier I wouldn't want to speculate on that, but the inquiry clearly needs to look at it."

London Fire Brigade said it cannot comment on its response to the fire due to the ongoing police investigation and public inquiry, but said "the advice our control officers give can change as the fire changes".

Meanwhile, in other developments:

Twenty-two housing offers have been accepted by Grenfell residents, up from 14 last Wednesday. Seventy-eight viewings have been completed and four households have been rehoused

Westminster coroner Dr Fiona Wilcox said 34 victims have been identified and that "work is ongoing and proceeding as well as it can, under trying circumstances"

She also suspended the 30 inquests opened so far, to allow the public inquiry and any criminal investigations to proceed

The Metropolitan Police confirmed the latest identified victim as 32-year-old Zainab Deen, but there is still no news on her son Jeremiah

First Secretary Damian Green told a parliamentary debate on the fire that the government would pay for tower block alterations recommended by the fire service, if councils cannot afford them

More than 200 firefighters and 40 fire engines were involved in battling the blaze that engulfed the block.

The BBC understands 31 firefighters were injured in the fire, almost all through smoke inhalation. One was hit by a person who fell from the tower, but insisted on returning to duty.