The former head of the British Army has warned of the dangers of making too many military cuts.
Lord Dannatt hit out over reports that the Army could be reduced by more than what was announced under the government's strategic defence review.
Speaking at the Hay-on-Wye festival, he also urged ministers to start planning now for post-Afghanistan operations.
The Army will cut up to 7,000 personnel over the next five years to leave a strength of around 98,000.
The former Chief of the General Staff said: "I personally worry about taking the Army in regular manpower terms much more below 100,000 or 95,000," he said.
"An Army as small as 80,000 will find itself very hard to operate."
'Pressure on families'
Speaking at the literary festival in Hay-on-Wye, Powys, he told the audience of the importance of future planning.
"A lot of thinking has got to go on now to ensure that we have got an Army that is large enough, well trained enough and a good sufficient flexibility to face whatever the future might throw at us," he said.
"We haven't really got that plan in place at the moment."
During his three-year tenure as head of the Army Lord Dannatt courted controversy by speaking out against the Ministry of Defence and the then Labour government.
He went on to complain publicly that troops were risking their lives for worse pay than that of traffic wardens.
"I could not have looked at myself in the mirror in the morning during those three years I was head of the Army if I hadn't done what I had done," he told the festival audience.
Lord Dannatt, who was Chief of the General Staff between 2006 and 2009, also said that in 2006 the Army was not capable of supporting two major operations in Iraq and Afghanistan.
"I was not convinced I was able to get that point over to the government of the day or indeed colleagues on the Chiefs of Staff Committee sufficiently to allow that to work through in the normal way into Whitehall bureaucracy," he said.
"My real worry was that the pressure on our people and their families of the accumulation of difficult six month tours was that we were going to go into freefall and make our circumstances even more difficult."
'Call Scotland's bluff'
Lord Dannatt also called on the Prime Minister David Cameron to "call Alex Salmond's bluff" over Scottish independence.
He said he did not believe Scots would vote for independence and said: "If I were David Cameron I wouldn't wait until Alex Salmond decided when the right moment was to hold a referendum, I'd call one in a year's time and call the Scots' bluff."
Lord Dannatt, who was born and educated in Essex and now lives in Norfolk, said: "I can understand the Scots' desire for a greater degree of independence but when you really stare down the barrel of complete independence and providing for their own security, I am not sure they would want to do that.
"They might go to some half-way house whereby defence and security of the British Isles remains on a UK-wide basis. I think anything else would be most unwise and I think the Scots would realise that."