Lives could be lost among Britain's armed forces if the government fails to adequately invest in defence, the former head of the Royal Navy has said.
Admiral Sir Alan West said it was vital that the UK pressed ahead with plans to build two aircraft carriers.
He said the Army might not in future be able to deal with dangerous situations around the world which demanded "proper, balanced forces".
"Our forces are among the best equipped in the world," an MoD spokeswoman said.
Sir Alan, who retired this year, said: "If you do not buy the equipment, if you do not buy expensive equipment to do this, the right equipment, you end up with people at risk and you lose lives.
"I could see us in a position where we could have British servicemen's - that is Navy, Army and Air Force - lives being lost because we have not made the sort of investments in things like the aircraft carrier."
Sir Alan said that the world was likely to become more dangerous in the future.
He warned that in future the Army might be capable "of gendarmerie operations against terrorists in Central Asia" but not able to handle "greater risks around the world where we actually need proper balanced forces".
Sir Alan went on: "I believe that Gordon Brown and this government are firmly behind these aircraft carriers but of course they listen to advice within the ministry, within that area.
"If people are starting to say, 'Oh goodness me couldn't we use this money elsewhere? Couldn't we do something else?' then they might listen to those appeals."
Sir Alan told the Sunday Telegraph that the Royal Navy's aircraft carrier programme was the "jewel in the crown of the strategic defence review".
He said he had set aside £3.5bn for the project, but warned: "There are officials within the MoD who are casting lascivious looks at [the programme]."
Sir Alan suggested that this aircraft carrier programme was important because it was vital that security problems could be "nipped in the bud before developing".
He said the UK population needed to realise the importance of defence in maintaining the success of the country.
However, a spokeswoman for the MoD said the defence budget for 2007-8 would be £3.7bn higher than in 2004-5 in real terms.
"We are using these extra resources to modernise our armed forces to meet the challenges of the 21st Century," she said.
Sir Alan is the latest senior military figure to speak out about issues affecting the armed forces.
In October, army head Gen Sir Richard Dannatt said in a newspaper interview that the presence of UK troops in Iraq "exacerbates the security problems" and they should "get out some time soon".
And his predecessor Gen Sir Mike Jackson earlier this month criticised the Ministry of Defence's running of the armed forces.