A former British Army commander has accused Tony Blair of putting soldiers at "considerable and quite unnecessary risk" with cuts in defence spending.
Sir Michael said it was "heartening" Army bosses were speaking out
General Sir Michael Rose told the Independent on Sunday that despite statements to the contrary troops were not getting the support they should.
The "military ethos" was being undermined by new laws, he said.
But the Ministry of Defence said it recognised the importance of investing in the armed forces.
The ex-Bosnia UN chief's comments come in the wake of calls from the head of British forces in southern Iraq for national support for soldiers serving in the country.
Issues such as underfunding had to be addressed to maintain their quality of work, Major General Richard Shirreff said, but the Ministry of Defence said spending had risen steadily.
Writing in the paper, Sir Michael said although Defence Secretary Des Browne maintained there had been an increase in spending in the last three years, most had gone on technical programmes such as Trident replacement.
He said: "In the past six years, the prime minister has presided over a near-catastrophic decline in defence spending which has put our soldiers in Iraq and Afghanistan at considerable and quite unnecessary risk."
"For fighting insurgencies such as those in Afghanistan and Iraq we need rather large numbers of soldiers on the ground, proper protection and tactical mobility, including helicopters," he added.
"The infantry is the vital combat arm in insurgency warfare, yet manpower has continued to fall."
He said that it had been "tremendously heartening" for servicemen and women to see senior military "standing up for them" by speaking out about resources.
Health and safety and equal opportunity laws and "risk management" were damaging the military ethos, he said, adding that good command and effective military tactics were better than "imposed civil law".
On President George W Bush and Tony Blair's handling of Iraq, Sir Michael wrote: "They tell us it is the Iraqi government that runs the country.
"This is disgraceful hand-washing. They know, under the Geneva Conventions, they were responsible for the disastrous breakdown of law and order in the country they invaded."
But he said Mr Bush had at least "put his money where his mouth was" by giving resources and support to his troops.
Sir Michael has previously called for Mr Blair to be impeached over Iraq, for going to war on "false grounds".
An MoD spokesman said: "Defence spending has been steadily increasing.
"Last year alone we spent more than £700m on improvements to service housing, announced the introduction of a new £2,240 operational bonus and invested millions more in new equipment, including body armour and armoured vehicles."