"I think that the London Fire Brigade from Danny Cotton, the commissioner, all the way down to some of the new guys who have just joined, I think everybody worked damn hard that night," he said.
"Firefighters like myself and many other firefighters that night went into the building and risked their own lives to save others."
Diana, who rescued nine people and carried one survivor down at least 13 floors, added: "We did what we could that night, the fire service and everybody else worked as hard as they could that night. Some of the guys I went in twice on that night and I know guys who went in three times.
"When you are trying to wear a breathing apparatus set, full gear, you're drained from the first. I went up and down those stairs six times. Up and down half way up that building six times."
His comments come a day after Paulos Tekle, whose 5-year-old son Isaac Paulos died as they tried to escape, told the public inquiry that if he "had not listened to the fire brigade my son would likely be alive today".
Diana said that he was one of the later crews to arrive, after 2am, and therefore did not know anything about the 'stay put' policy.
"I was there as a firefighter to save life, so I can't answer that stay put advice," he told BBC Radio 4's Today.
He said that he also could not answer whether the advice needed to change in other tower block fires, but noted that in his experience: "Fires don't spread the way that that did".
"This fire was totally different to anything that I have been in, fire's don't spread the way that this one did, normally they are contained in the one room or the one flat that they start in they may go to a flat one above or one flat to the left or right," he said.
"But never in the 26 years I have been in has a fire jumped or gone round the building such as this one did. So people are generally, 99pc of the time, safe."
It was announced today that around round 4000 doors on homes in the Royal Borough of Kensington and Chelsea, where the fire took place, are set to be replaced with ones which are fire-resistant for 30 minutes, the time stipulated in the current Building Regulation standards.
In March, it was revealed that an undamaged door from the Grenfell tower block was tested and found it could only withstand a blaze for 15 minutes - not the 30 for which it was designed.
Plans for the £3.5 million project will be discussed next week. The authority said the doors it would be replacing are "not necessarily deficient" in terms of fire risk assessments.
It added: "This is not currently a legislative requirement, but this may change following the completion of the current building regulations review."
Meanwhile, a report has found that voluntary organisations filled the void left by a lack of official direction in the wake of the disaster.
The report, Mind The Gap: A Review Of The Voluntary Sector Response To The Grenfell Tragedy, found that many voluntary organisations stepped up to the challenge of meeting the needs of the community where the statutory authorities fell short, particularly in the early stages.
