General Sir Mike Jackson, the former head of the Army, has criticised the way in which the Ministry of Defence (MoD) runs the armed forces.
Speaking at the annual Dimbleby Lecture, he said soldiers' wages were "hardly impressive" and "some accommodation" was "frankly shaming".
But the MoD said it was always working to improve conditions for its forces.
Conservative defence spokesman Dr Liam Fox said Sir Mike's comments were damning for the government.
Sir Mike retired as the head of the Army in August. He told the BBC he had not spoken out while in his post but now he was "a civilian".
He said: "It's not a question of whether I say things or not, it's a question of whether you say things publicly or not."
During his speech he questioned the MoD's understanding of the fundamental ethos of the armed forces.
Sir Mike later told the BBC: "It's a sense of shared endeavour, a sense of being a member of the team.
"Unless you have that glue which keeps the army together....you will not have an army worth the name."
Sir Mike also suggested in his speech that not enough was being done to care for servicemen and women, as well as their families.
"Not much over £1,000 a month for the private soldier for what he or she is doing on operations is hardly an impressive figure."
During his speech, he hit out at a "Kafka-esque situation whereby the MoD congratulates itself on achieving an accommodation improvement plan defined by itself on what it calls affordability, but which is far from what is defined by the needs of soldiers and their families".
Sir Mike says troops should not leave Iraq until the time is right
Sir Mike said he did have sympathy with the tasks facing the MoD: "I understand all the problems for the Ministry of Defence, of course I do, working within a budget and trying to do so many things is not easy.
"But I don't feel we just get there all the time, and we should."
He also said young people who "put their lives at risk" for the benefit of the country are owed "the tools to do that job".
When asked about the military campaign in Afghanistan, Sir Mike replied that "anybody who thought it was going to be a picnic had not thought it through".
He also said the Coalition forces in Iraq should not be "mesmerised" by any date set for a withdrawal, because "conditions must be right" before troops could return home.
The Conservative defence spokesman, Dr Liam Fox, told BBC Radio 4's Today programme Sir Mike was attacking "this target culture of the MoD".
He said: "They measure not what is necessary but what is measurable and therefore you very often end up with results which suit the government statisticians but not those who are actually on the front line.
"We're actually spending 2.5% of our GDP this year - which is our lowest since 1930 - but at a time when our commitments are rising."
BBC defence correspondent Paul Adams said the comments were "bound to cause offence in some circles" and were likely to be "taken seriously" by those high up within the MoD.
But our correspondent went on to say Sir Mike was "not universally respected", adding that some people may think "it is a bit late to stand up for the common soldier", given his recent retirement.
A spokesman for the MoD said: "General Jackson is fully entitled... to voice his opinion on these important issues."
"While we do not agree with everything Sir Mike has said, we are always the first to recognise - for example in relation to medical services and accommodation - that although we have delivered real improvements, there is more we can do.
"We are always striving to make things better for our forces and we are always open to informed criticism."