Having more helicopters available in Afghanistan would make no difference to the current mission, Chief of Defence Staff, Sir Jock Stirrup, has said.
An extra 125 servicemen and women are to be deployed to Afghanistan to reinforce the operation, Defence Secretary Bob Ainsworth has announced.
"You've got to fight your way through on foot. There is no alternative," he told BBC's World at One.
The move follows calls from commanders on the ground for more troops, as well as equipment for them.
However, last week he said additional helicopters would "quite patently" prevent casualties and appealed to the government for more.
The Ministry of Defence has denied his comments were contradictory.
UK forces are currently engaged in a major offensive - known as Operation Panther's Claw - against insurgent strongholds in Helmand.
UK forces are currently engaged in a major offensive - known as Operation Panther's Claw - against insurgent strongholds in Helmand.
In the past month, 19 British servicemen have died there.
In the past month, 19 British servicemen have died there.
You can't get through this defensive crust of improvised explosive devices with helicopters Sir Jock Stirrup Chief of Defence Staff
Mr Ainsworth said: "I have always said that I will listen to the view of commanders on the ground in Afghanistan - they are the people best placed to know the resources needed for that operation.
Critics of the government have claimed commanders on the ground do not have enough helicopters.
"In this case they have told me that, after the sad and tragic casualty rate that we have suffered in recent weeks, reinforcements are necessary to ensure we can maintain our operational tempo and consolidate the real progress we have made.
However, Gordon Brown insists the UK has sufficient helicopters for the Helmand mission while Defence Secretary Bob Ainsworth says he is "busting a gut" to get more out to Afghanistan.
"These additional troops will ensure we have sufficient troop levels and, crucially, the right specialist skills in theatre.
In the BBC interview, Sir Jock said: "They [helicopters] are very useful and they certainly provide much more tactical flexibility, they enable you to be unpredictable and therefore they make it harder for the enemy to target you with improvised explosive devices.
"Many of our brave young men have died fighting to protect our national interest in Afghanistan and I will not allow their sacrifices to have been in vain."
"But on operations such as this... you can't get through this defensive crust of improvised explosive devices with helicopters.
"You've got to fight your way through on foot. There is no alternative.
"Helicopters were used in this operation but more helicopters, had they been available, would have made no difference," he added.
Last week, he insisted he had always said there was no such thing as enough helicopters in an operation campaign, explaining that they increased "tactical flexibility" allowing the enemy to be outfoxed.
'Achieve more'
A spokesman for the Ministry of Defence said: "There's no contradiction. The point we are making is that we have got sufficient helicopter resources to do what we are doing at the moment.
"If we had more helicopters, we could make progress quicker and achieve more.
"We are working to get more helicopters into theatre. When we do, that will aid our operations."
He added that most of those whose lives were lost would not have been saved by more helicopters, as they were on foot patrol.
He went on to say that Sir Jock spoke to the prime minister on a weekly basis and was "always willing to be frank" with him.
Asked whether Sir Jock's comments were a sign he was reining in his criticism of the government, the spokesman said it was doing Sir Jock a disservice to suggest he could be "silenced".
