Nato leaders are set this week to agree deep cuts to the alliance's command structure, mirroring defence cuts across the member states.
Prime Minister David Cameron and other alliance leaders gathering in Lisbon for a two-day Nato summit are expected to sign up to a "leaner" command structure which will see the number of headquarters personnel reduced by a third.
Currently, some 13,000 military personnel are seconded from member states' armed forces to serve in the various Nato headquarters.
British officials preparing for the summit hope that that figure can be held down to around 9,000 - saving "tens of millions of pounds" from the UK defence budget.
The changes will also see the number of designated Nato headquarters within the alliance cut, and number of Nato agencies - covering such aspects as logistics and communications, research and training - reduced from 14 to three.
Nato Secretary-General Anders Fogh Rasmussen said in a recent BBC interview that the alliance needed to face up to the current "economic realities".
"All allies are faced with budgetary constraints so my suggestion is that we focus on making more efficient use of resources within restrictive budgets," he said.
The summit is also expected to confirm a new Nato "strategic concept" - the first since 1999 - setting out the organisation's guiding principles.
While it reaffirms Nato as the "bedrock" of the alliance members' collective defence, it also deals with emerging threats such as cyber attack.
The meeting will also set out further details of the process of transferring responsibility for security in Afghanistan from international forces to the Afghan authorities, which is expected to begin next year.