The senior firefighter who revoked the order for Grenfell Tower residents to stay in the burning tower block has been appointed commissioner of the London fire brigade after Dany Cotton was forced out last week.

Andy Roe, a former army officer and a firefighter with 17 years’ experience, was the most senior incident commander during the disaster on 14 June 2017. He revoked the “stay put” policy which has been blamed for costing lives as soon as he took control at 2.47am.

Cotton resigned on Friday after a delegation of bereaved families called on the London mayor, Sadiq Khan, to remove her after stinging criticism of the LFB’s planning and response to the fire. Her resignation was welcomed by the bereaved and survivors but Matt Wrack, the leader of the Fire Brigades Union, claimed she was among firefighters being “scapegoated” and the decision to remove her had caused shock and anger among the rank and file.

The change of leadership at the LFB comes six weeks after Sir Martin Moore-Bick, the chairman of the public inquiry into the disaster that claimed 72 lives, said the LFB’s readiness was “gravely inadequate” and fewer people would have died if it had been better prepared.

He said the absence of an operational evacuation plan was “a major omission” and the LFB was guilty of “institutional failure” to inform firefighters about the risks of cladding fires before the disaster. On the night of the fire there was a “failure of command” which meant firefighters with extended-duration breathing kits were deployed too slowly, he said.

Roe told the inquiry that as he travelled to the fire, receiving pictures and telephone updates, he already thought that his focus would be on saving residents rather than trying to put the fire out. As soon as he arrived and took over command of the incident, he said he knew the stay put policy was “absolutely unsustainable”. He revoked it at the same time as call handlers were asking for it to be changed and from that point residents were told to try to get out.

Khan said on Tuesday that Roe would be responsible for the “transformation of the brigade … as swiftly as possible”.

“The Grenfell Tower inquiry report made it clear there were institutional failures that meant, while firefighters performed with great courage and bravery, the overall response to the disaster was not good enough and there are significant lessons for London fire brigade,” he said.

Roe was in charge of the operational response to the Croydon tram crash in 2016, which killed seven people. He was made assistant commissioner in January 2017 .

He said: “It is an enormous privilege to be offered this opportunity to lead London fire brigade into a new decade. We have some real challenges ahead but I’ll be working tirelessly with the brigade, the mayor and London’s communities to ensure we deliver on the recommendations of the Grenfell Tower inquiry report.”