Top Four Threats To Britain's National Security

Prime Minister David Cameron has said investment to bolster Britain's ability to combat the threat of global terrorism and cyber criminals is a "national necessity" for the Armed Forces to deal with new "unseen enemies".

He has pledged a £1.1bn package of investment in "vital" military programmes to meet new threats posed by global terrorism and cyber criminals.

According to British intelligence agencies MI5 and MI6, terrorism, espionage and the proliferation of weapons of mass destruction (WMD) pose the biggest ongoing threat to national security:

Terrorism

The biggest national security threat Britain faces - and the most significant threat to the UK and its interests overseas comes from groups such as al Qaeda.

The greatest threat comes from its leadership and affiliate groups:

:: North Africa (Sahel region): Al Qaeda in the Islamic Maghreb (AQM) which aims to overthrow the Algerian government and declare an Islamic state.

:: East Africa (Somalia): Al Shabaab was formed to fight for a strict interpretation of Sharia law in Somalia but in recent years has broadened its aims to include international jihad operations. Insurgents have claimed recent attacks in Kenya and Djibouti, and at home in Somalia.

:: Yemen: Al Qaeda in the Arabian Peninsula (AQAP), formed in 2009 following a merger between Yemeni and Saudi branches, has attempted to appeal to Yemen's various anti-government groups. The US regards AQAP as al Qaeda's most dangerous franchise.

:: Iraq: Hundreds of Britons could be fighting with the Islamic State in Iraq and Syria (ISIS), the extremist group which has taken over large parts of Iraq after splitting from al Qaeda earlier this year.

:: Syria: Members of al Qaeda's Syrian affiliate al Nusrah Front are now said to have recently sworn allegiance to ISIS.

A recent notable concern involves AQAP and al Nusra Front. It is believed bomb-makers from both al Qaeda affiliates are working together to create non-metallic bombs that could evade metal detectors. This has led to security being tightened at UK airports.

Espionage

Spies are no longer just targeting political and military intelligence, but in today's technology-driven world, defence, IT, communications, intelligence services scientific research, as well as other government-related organisations are all vulnerable to espionage.

Cyber attacks

While it does not name all the countries, at least 20 foreign intelligence services are said to be actively operating against UK interests, including Russia and China, according to MI5.

Foreign states, terrorists, criminals, individuals and 'hactivist' groups are equipped to steal, alter or destroy computer networks, information systems and infrastructures by using malicious software, posing a grave threat to the UK's economic stability and national security.

The proliferation of weapons of mass destruction (WMD)

Several countries are actively pursuing WMD - nuclear, chemical and biological - programmes and have sought to "illicitly obtain equipment and expertise from the UK, according to MI5.

The regimes perceived as a threat are those which have not signed up to the Non-Proliferation Treaty, those who pursue clandestine weapons programmes and those who act in contravention of United Nations Resolutions to limit the build up of nuclear weapons.

Iran, North Korea and Syria are among the countries of concern.