The Prime Minister has pledged 3,500 British troops to take part in exercises in eastern Europe in 2015 and 2016.
The Prime Minister has pledged 1,000 British troops to a "high readiness" Nato force, Downing Street has said.
When the force is ready, in late 2015, it will be capable of deploying within 2-6 days.
British troops will make up a substantial portion of the multinational force, which will total 4,000 troops.
The Ministry of Defence announced today a deal to buy new £48 million state-of-the-art missile system for Royal Navy helicopters.
The defence minister Philip Dunne said the system made in east Belfast by the defence company Thales UK "will help win battles."
Mr Dunne said coastlines represented areas of growing concern to armed forces around the world and this new technology would provide greater protection.
The system will be used to target small ships and fast attack craft and be designed and built by Thales UK's Belfast plant.
Conservative MP Rory Stewart has been elected the new chair of the House of Commons Defence Select Committee, taking over from fellow Tory James Arbuthnot.
Mr Stewart, who represents the Cumbria constituency of Penrith and The Border, has served in the army and the diplomatic service, along with running a charity in Afghanistan.
The Government has dodged criticism that it is not clear enough on its military intervention policy, saying it will allow the House of Commons to debate before sending troops to overseas crisis.
A Government spokesman said:
The decision to use UK armed forces overseas is among the most significant a Government can make.
That's why the Government has stated that it will observe the existing convention that says the House of Commons should have the opportunity to debate before UK troops are committed to conflict, except in cases where the urgency of the action required makes this impossible.
Military intervention as a course of action can of course be contentious and contested but the Government is clear that it remains an important last resort when all other means of dealing with threats have been exhausted.
Opting out of military intervention in international crisis has "implications for the UK's place in the world," MPs have warned.
A report from the Defence Select Committee said:
We understand and acknowledge the current lack of appetite for military operations given the experiences and tensions of the past decade for operations in countries such as Afghanistan and Iraq.
However, it is also necessary to understand and acknowledge that there are consequences to decisions by the UK and the international community not to intervene in humanitarian or non-humanitarian situations.
Non-intervention decisions have implications for the UK's place in the world and its influence which are as profound as a decision to undertake an intervention operation.
The Government should set out a "realistic vision" of the circumstances which would force the UK to join military intervention abroad, a committee of MPs have recommended.
The cross-party Defence Select Committee called on the Coalition to set clear parameters for the kind of behaviour which would force them to send troops abroad.
MPs also called on David Cameron's Government to clearly define the UK's place in the world.
Committee members warned the implications of not joining some crisis were just as profound as sending troops abroad.
The MPs suggested Russia may have felt empowered to intervene in Ukraine because the UK and other countries had failed to act in Georgia or Syria.
Thousands of defence jobs will be at risk if Scotland votes for independence in September, according to Defence Secretary Philip Hammond.Read the full story ›
Thousands of defence jobs will be at risk if Scotland votes for independence in September, according to Defence Secretary Philip Hammond.
Mr Hammond warned workers at the Glasgow-based firm Thales that their future prosperity, and that of their families, would be put in jeopardy by a Yes vote for independence.
He said: "The creation of a border between this facility and its largest customer will put at jeopardy the future prosperity of this business, the people who work in it and their families and dependents."
"If we were to separate, then the future of the defence industry in Scotland that depends on MoD orders will be put at risk," he added.
Scottish independence would "weaken" the effectiveness of the Royal Navy and damage "the very heart" of Britain's maritime defence forces, the First Sea Lord has warned.
A Yes vote would harm "the security" of Scotland and the rest of the United Kingdom, Admiral Sir George Zambellas told The Telegraph.
He said an independent Scotland’s claim on the Royal Navy would "greatly weaken the carefully evolved 'whole', as bases, infrastructure, procurement, spares, personnel and training face a carve up”.
“I believe that independence would fundamentally change maritime security for all of us in the United Kingdom and damage the very heart of the capabilities that are made up of the Royal Navy, the Royal Marines, the Royal Fleet Auxiliary and the Fleet Air Arm," he added.