UK defence is at a crossroads and decisions must be taken about what Britain's forces can and should do around the world, the shadow defence secretary will warn today.
Vernon Coaker will urge a more practical focus at the forthcoming Strategic Defence and Security Review (SDSR) rather than allowing the Treasury to run a rule over all the measures.
Withdrawal from Afghanistan and Germany opens the possibility of far-reaching debate, the Labour spokesman said.
He will also tell the Royal United Services Institute a "cyber-security charter" should be drawn up for all companies working with the Ministry of Defence (MoD), including a responsibility to report all cyber attacks in a bid to protect the MoD.
Speaking ahead of his speech, Mr Coaker said: "With UK defence at a crossroad, the time is now right to consider what role we want our forces to play in the world.
"We cannot afford for the next SDSR to be solely Treasury-led. Instead, we must ensure that the review provides the long-term direction that UK defence and security requires - one that is fiscally realistic and strategically ambitious.
"We are ambitious about the positive role that the UK Armed Forces and defence strategy can play in the world.
"And we are realistic in that we know we must strengthen and deepen our partnerships with existing allies, and seek to cultivate new ones, if we are to achieve our strategic objectives."
Mr Coaker will say Labour believes Britain has a growing role in stability actions, and will highlight participation with UN peacekeeping operations - three of which currently involve British forces.
And he will emphasise the need for increased specialisation amongst the troops, including engineers, logistics specialists, communication experts and medical personnel.
The opposition wants to see consultations on creating a legal obligation on firms to report cyber attacks which threatens national infrastructure. Any such consultation should consider what kinds of attacks would need to be reported, reflecting on the targets and reporting mechanism.
Every company working with the MoD, regardless of size, should sign up to a charter aimed at ensuring their systems cannot be exploited for access to other suppliers or the MoD itself.
Defence Secretary Philip Hammond said: "It's a bit rich for Labour to be calling for a strategic review of future threats and defence capabilities after they failed to have a strategic review for 12 years.
"The 2010 Strategic Defence & Security Review identified cyber threats and the need for upstream capacity building abroad as some of the priorities for the future.
"That is why hundreds of millions have been invested in these areas.
"After four years in opposition, Labour are calling for measures we already implementing; they still have no idea what they would do differently to the Government.
"Given the financial mess they left in defence, nobody can trust Labour with protecting the nation's security."