Factbox: Britain's National Security Strategy - key details

(Reuters) - Cyber attacks, terrorism, inter-state conflict and natural disasters top a list of threats to Britain's security, the government said Monday, announcing a new National Security Strategy.

The strategy underpins the principles behind a major military review -- the Strategic Defense and Security Review -- Tuesday, which is expected to outline deep spending cuts and the scaling back of big military hardware orders.

Britain's defense budget this year is 36.9 billion pounds ($58.6 billion) and is expected to be cut by about 7-8 percent over four years.

Here are some National Security Strategy highlights. Threats were categorized into levels depending on their likelihood and impact:

PRIMARY RISKS

* Hostile attacks on UK cyber space by other states and large scale cyber crime

* Chemical, biological, radiological or nuclear (CBRN) attacks from international terrorist groups such as al Qaeda

* A growing threat from Northern Ireland-linked groups

* Natural disasters such as severe coastal flooding affecting three or more regions of the UK

* The possibility of an influenza pandemic

* International military crises involving the UK and its allies

SECONDARY THREATS

* Attacks on the UK by another state using CBRN weapons

* Risk of insurgency or civil war overseas which could threaten the UK

* Increase in the level of organized crime affecting the UK

* Severe disruption to information received, transmitted or collected by its satellites.

OTHER CONCERNS

* A large scale, conventional military attack on the UK by another state

* Significant increase in the level of "terrorists," illegal immigrants and illicit goods entering Britain

* Conventional attack by a state on a NATO or EU member

* Attack on a UK overseas territory

* Disruption to Britain's oil, gas and food supplies

* A major release of radioactive material.

KEY QUOTES

* "The highest priority does not always mean the most resources."

* "The Olympics (2012 Games in London) will be an attractive target for criminals and others seeking to defraud and disrupt."

* "Our most urgent task is to return our nation's finances to sustainable footing."

* "We face no major state threat at present and no existential threat to our security, freedom, or prosperity."

* "We must also strengthen our network of bilateral ties ... a key feature of this change will be the rise of China and India as global powers"

* "Cyber-crime has been estimated to cost as much as $1 trillion per year globally"

* "In some cases, it may be appropriate to devote more resources to addressing risks which have low probability but very high impact; nuclear deterrence is an example of this."

* There will be a "transformative program for cyber security"

* "Al Qaeda remains the most potent terrorist threat to the UK"

* There is a "serious and persistent threat from residual terrorist groups linked to Northern Ireland"

(Reporting by Rhys Jones; Editing by Charles Dick)