Trapped Grenfell Tower residents told to stay put by 999 operators were not informed that the advice had changed unless they called 999 again, an inquiry has heard.
The London Fire Brigade control room had a policy not to re-contact callers, meaning those instructed to remain in their flats on June 14 last year received no update.
The standard high-rise policy to “stay put” in the event of a fire was ditched at 2:47am, nearly two hours after the blaze began.
Stay-put advice is given on the basis that a fire should stay within the flat of origin, but at Grenfell Tower it rapidly moved up the whole building.
Alexandra Norman, the most senior supervisor at the control room when the fire started, told the inquiry into the disaster that it would have been "impossible" to ring everyone back as hundreds of calls came in throughout the night.
‘We would not be able to continue taking 999 calls’
The inquiry's top lawyer, Richard Millett QC, asked Ms Norman how residents could know an evacuation was later advised if they were not contacted.
She replied: "That is a really hard one, but with the amount of calls we had on that night still coming in and the amount of calls we had already received, we would not be able to continue taking 999 calls.
"The hope would be that those callers would be calling us back to say conditions had worsened so we could give them that advice."
Mr Millett responded: "So you were relying on them to call back in?"
Ms Norman said: "At that point, yes.”
The control room received more calls requiring fire survival guidance (FSG) that night than in all of the previous decade across the capital.
There were initially 11 staff on duty at the main office in Stratford, east London - three supervisors and eight call operators.
Other emergency communication hubs across the country began helping out with calls as the situation worsened.
‘It would be impossible’
Ms Norman told the hearing at Holborn Bars on Thursday that she was "shocked" to see how quickly the fire developed, with a request for 10 engines jumping to 20 within minutes.
Mr Millett asked whether there was a specific reason why an operator would not contact an individual if the stay-put advice changes.
Ms Norman added: "It would depend on the amount of callers you needed to call back, the amount of calls coming into the control room.”
"If you have got lots and lots and lots of calls waiting to be answered and you have taken hundreds of calls already, it would be impossible to search through every single call to find the telephone number to re-contact them."
The temporary operations manager said there had never previously been an occasion where she needed to ring back someone with updated advice.