Sir Richard retires from his post later this month
More troops are needed in the Afghan province of Helmand to provide security, the outgoing head of the British Army has told the BBC.
General Sir Richard Dannatt said "more boots" were needed, whether they were British, American or Afghan troops.
His comments come after 15 UK soldiers were killed this month and a political row over resources for British troops.
Gordon Brown said the government was doing "everything we can to support our brave and courageous armed forces".
On his last trip to Afghanistan before retiring this month, Gen Dannatt told BBC Radio 4's Today programme: "I have said before, we can have effect where we have boots on the ground.
"I don't mind whether the feet in those boots are British, American or Afghan, but we need more to have the persistent effect to give the people (of Helmand) confidence in us.
"That is the top line and the bottom line."
He was speaking the day after the bodies of eight British servicemen killed in Afghanistan - three of them teenagers - were repatriated to Britain.
Asked why he was flown around Afghanistan in an American helicopter he said it was because he did not have a British one.
"There is a pool and we share the assets, but we have got to put as much into the pool as we take out."
On whether Britain's 9,100-strong force in Afghanistan has the equipment it needs, he said: "We are building our resources up.
"In terms of equipment, we have got a plan to increase the amount of campaign equipment we've got.
"It has probably not moved as fast as I would have liked it to have moved, but we are increasing the numbers.
"I would like to get more energy behind it if we possibly can."
Downing Street said Britain was calling on other Nato countries to provide more troops to Afghanistan.
The prime minister's spokesman said: "We do need to have more of an effort from other Nato members.
"The PM's view is we need to see more burden-sharing."
The government had kept the level of British troops under review, with the number increasing from 7,800 last year, to more than 9,000 now, said the spokesman.
The situation in Afghanistan dominated prime minister's questions in the House of Commons on Wednesday.
Conservative leader David Cameron complained that UK troops had just 30 helicopters to call on in Afghanistan - out of the UK's total military fleet of some 500 - compared with about 100 in operation for the same number of US troops.
He said the relatives of those serving in Afghanistan wanted to know ministers had a "relentless commitment" to providing all the resources necessary.
"We have to be frank about the dangers and difficulties in Afghanistan and one of the difficulties is a shortage of helicopters," Mr Cameron said.
The prime minister responded: "We have done everything that we can to increase the number of helicopters and there will be more Merlin helicopters on the ground.
We have to make sure that terrorism cannot hit the streets of Britain and that's why we cannot allow the Taliban or al-Qaeda-related activities to flourish
Prime Minister Gordon Brown
"And I do ask the Conservative Party to look at the statements that are being made by those people who speak for our armed forces on the ground; they have made it absolutely clear that in this particular instance, while the loss of life is tragic and sad, it is not to do with helicopters."
The prime minister said army chiefs in Afghanistan were satisfied they had the equipment to do the job asked of them and the army was better equipped than ever.
"I believe we are making the provision necessary for helicopters and equipment on the ground," he said.
Mr Cameron insisted that he supported the UK mission in Afghanistan, but complained of "lofty and vague" aims and a need for a more tightly-defined campaign mission.
But Mr Brown said: "The purpose of our mission is very clear: to prevent terrorism coming to the streets of Britain."
He said "complementary action" was under way in Afghanistan and Pakistan, as a "necessary means of defeating terrorism in the world".
"It was true in 2001 that al-Qaeda was given cover by the Taliban in Afghanistan. It's also true that al-Qaeda is mainly based in north Pakistan now.
"We have to make sure that terrorism cannot hit the streets of Britain and that's why we cannot allow the Taliban or al-Qaeda-related activities to flourish in Pakistan and we cannot allow the Pakistan government to be over-run by people operating through al-Qaeda and the Pakistan Taliban.
"What's encouraging ... is that for the first time we see the Pakistan government taking direct action in a systematic way, with the support of the population, against the Taliban and against al-Qaeda."