Philip Hammond is expected to confirm 1,400 job losses in the Army but the Head of the Army said there will be no more "forced exodus".
The Defence Secretary has defended the use of unmanned aircrafts as the UK's drone nerve centre was revealed for the first time.
The Ministry of Defence has confirmed how much it has spent on the failed attempt to part-privatise its defence procurement arm.
Defence Secretary Philip Hammond told ITV News' Deputy Political Editor Chris Ship that "you can never be 100% sure there won't be collateral damage", as the RAF unveiled its nerve centre of a controversial drone programme for the first time today.
Mr Hammond added: "We only know of one strike where there were civilian casualties. But of course, civilian casualties have also resulted from strikes by manned aircrafts. That is the nature of warfare".
The Ministry of Defence has said the analysis into scrapping plans to privatise the government body which buys defence equipment provided "invaluable insight".
An MoD spokesperson said the amount spent represents "a very small proportion" of the £14b DE&S budget.
– Ministry of Defence
We have invested in detailed analysis to not only fully understand the problems in DE&S but thoroughly scrutinise the various options for how to improve the complex defence procurement process.
This analysis has provided invaluable insight that will help to deliver long term savings as we transition to a new organisation.
Defence Secretary Philip Hammond has urged Tory backbenchers to give his plan for recruiting more than 10,000 Army reservists a chance, instead of "throwing roadblocks".
Responding to accusations that recruitment targets for the Army Reserve have been missed, he said it was still early days and that he would not tolerate a halt in that process.
He also accused opposition parties of exploiting a Tory rebellion for political advantage.
The Defence Secretary Philip Hammond has said Britain must never forget the ultimate sacrifice of the 446 servicemen and women who have died in Afghanistan, as the country prepares to pay tribute to those who have died in major conflicts.
Mr Hammond said this year's service in Camp Bastion, in Afghanistan will hold particular significance as it will be the last large-scale act of remembrance in the country before more troops are recalled ahead of the completion of operations at the end of next year.
"As we get closer to the culmination of this 12-year campaign, it is right to reflect upon the sacrifices that have been made by the brave men and women of our Armed Forces, and their significant achievements", he wrote in The Sun on Sunday.
"Four hundred and forty six British servicemen and women have made the ultimate sacrifice in Afghanistan on our behalf, putting their lives on the line to protect us. We should never forget them and we should never forget their families, who are forever without their loved ones."
Mr Hammond also said the dedication, professionalism and courage of Britain's armed forces was "truly the finest in the world".
After the UK's most senior general admitted an Army recruitment drive for part time soldiers had got off to a "wobbly start" there have been concerns about whether the Ministry of Defence will hit its ambitious targets.
In order to offset a cut of 20,000 in the size of the Regular Army - the MoD is committed to increasing the size of the Army Reserve (the new name for the Territorial Army) by a third - from 19,000 to 30,000.
Leaked memos have suggested the target will be very difficult to reach.
However, the Defence Secretary has just told the House of Commons that 1,576 applications have been received since the campaign was launched.
And last week the Army Reserve recruitment team received 380 applications.
Given the MoD needs only to recruit an average of 42 reservists per week, it would appear this target might be easier to reach than even the MoD's own generals anticipate.
Defence Secretary Philip Hammond has set a target of recruiting 10,000 army reservists in five years.
He revealed that there have been 1,576 applications so far.
Mr Hammond said he shared the confidence of the Chief of the Defence Staff, Sir Nick Houghton, that the UK would eventually meet the target of 30,000 army reservists.