Four Grenfell Tower residents were accidentally left to die in an upper-floor flat after a calamitous mix-up during the rescue effort, an inquiry has heard.

Eight tenants from the 14th floor had been told by firefighters to hunker down in flat 113 and await rescue – but only four were taken out.

It emerged at the Grenfell Tower inquiry on Thursday that the team tasked with saving them were under the impression only a family of three were in the flat.

But, in an extraordinary divergence of accounts, rescuer Peter Herrera had his story called into question by survivor Omar al-Haj Ali, whose brother Mohammad died that night.

The Lambeth firefighter was accused of being “mistaken” – and challenged about how he could have missed four people in the flat if he had “looked properly”.

Mr Herrera insisted he did not “make this up”, but closed his evidence saying he was “very, very, very sorry” if anyone thought he had failed them.

He told the hearing at Holborn Bars he had arrived at flat 113 to find the electricity out and the family of three – Oluwaseun Talabi, his partner and their young daughter.

The family were “reluctant” to leave, but he pulled them out and sent them down the stairs with his colleagues.

He then noticed a “silhouette” in the flat, according to his written statement, which transpired to be Omar al-Haj Ali.

Omar had been with Mohammad and their 14th-floor neighbours Denis Murphy, Zainab Deen and her young son Jeremiah.

The firefighter asked the man if anyone else was left in the flat and was allegedly told: “No, I’m the last one.”

Omar was quickly rushed down the stairwell with Mr Talabi and his family.

The firefighter claimed he only realised the mistake later in the night, when he saw Omar on the phone to his trapped brother outside the tower.

His statement said: “He then went on to say, ‘I am still on the phone to him, he is on his knees praying’. He also said, ‘I was mistaken’.

“I remember saying to (crew manager Benjamin McAlonen), ‘oh f***’.

“There seemed to be some confusion as I recall ‘Syrian man’ being very clear earlier that no-one else was in the flat. I said to him ‘don’t worry, I will sort it out’.”

But his version of both conversations was hotly contested by Mr al-Haj Ali.

The survivor, who was present at the hearing along with Mr Talabi, claimed he never said the flat was empty, nor did he later admit being “mistaken”.

Counsel to the inquiry Andrew Kinnier QC said: “Mr al-Haj Ali wants me to suggest to you that the account of that conversation is mistaken – would your response be effectively the one you have already provided?”

“It must have been a mistake on one of our parts, yes,” Mr Herrera said.

Mr Kinnier continued: “Mr al-Haj Ali would want to say that you didn’t come into the lounge – what would you say to that?”

He replied: “I was there and I know what I did – I spoke to the gentleman, he was there, I was there. I didn’t make this up, I was with him.”

The firefighter said he did not search the remaining rooms as he “assumed there was no-one there”.

Several of the remaining residents were found dead within flat 113, the inquiry was told.

Mr Herrera was asked by Mr Kinnier why he did not notice them, “if they were in there, if you looked properly”.

He replied: “That’s the thing, I didn’t see them, they weren’t there.

“Especially if I’m being told he was the last person, there was no need to look, from my point of view that flat was empty.”

Mr Talabi could be seen shaking his head at the answer.

Earlier, the firefighter who made the initial decision to move the 14th-floor residents into one flat also apologised.

Desmond Murphy, a firefighter from Kensington, assessed it was too dangerous to take the group down the smoke-logged stairwell and found flat 113 to have safe air.

He, colleague Charles Cornelius and two firefighters from Acton including Nicke Merrion were forced to leave for the lower floors as they ran low on oxygen.

They told their superiors at the operational hub that eight people, six adults and two children required rescue in flat 113, the inquiry was told.

Working hard to maintain composure, Mr Murphy told Thursday’s hearing: “I would just like to say to the family members of Denis Murphy and the family members of the other seven residents I came into contact with on the 14th floor – I’m very sorry we couldn’t get your loved ones out of the building.”

Mohammad al-Haj Ali, Ms Deen and her son and Denis Murphy all died in the fire.