Foreign Policy is one of the key issues that has been focused on during the British election campaign. So where do Labour, the Tories and the Lib Dems stand regarding the most popular Foreign Policy issues?
Britain joined the EEC, forerunner of the EU, in 1973, but many UK citizens remain hostile to greater European integration.
Mr Brown's predecessor, Tony Blair, pledged to put Britain at the heart of Europe, but Britain stayed out of the Euro single currency and the Schengen borderless travel zone and negotiated a series of exemptions from the EU's Lisbon reform treaty.
• The Liberal Democrats are the most pro-European of the three parties with Mr Clegg being a former MEP. They back joining the Euro single currency in principle, but say the economic conditions mean now is not the right time to do so. They also say they would hold a referendum before entry. The Lib Dems propose closer European security and defence co-operation. They also say there should be a referendum on whether Britain stays in or pulls out of the bloc next time Britain signs a new EU treaty.
• Labour is broadly pro-European but does not want a federalist EU. It also supports joining the Euro at a more suitable time and after holding a referendum on the decision. Labour supports Turkish membership of the EU.
• The centre-right Conservatives want Britain to stay in the EU but they oppose moves towards a federal Europe and want to repatriate some powers from Brussels. Mr Cameron has said he would try to negotiate the return of Britain's opt-out in some areas of EU social and employment law, take back powers on criminal justice and gain a complete exemption from the EU's charter of fundamental rights. The Conservatives would pass a law requiring a referendum on any future treaty that transfers power from Britain to the EU. They do not support Britain joining the Euro. They also back Turkish membership of the EU.
• Labour and the Conservatives say that with states such as Iran suspected of seeking to acquire nuclear weapons, now is not the time for Britain to disarm unilaterally. Both parties are in favour of renewing Trident, Britain’s submarine-based nuclear missile system, in order to maintain the UK’s independent nuclear deterrent.
• The Liberal Democrats rule out like-for-like replacement of Trident, which they say would cost £100bn. They would, however, keep some form of nuclear deterrent and propose alternatives to buying new submarines, such as extending the life of Trident or putting nuclear missiles on conventionally-armed submarines.
While Labour and the Conservatives backed Britain's involvement in the 2003 US-led invasion of Iraq, the Lib Dems opposed the invasion from the outset.
• Labour stands by the decision to invade Iraq, with Gordon Brown saying it was made necessary by Saddam Hussein's flouting of UN resolutions. Mr Brown has vehemently denied claims that as Chancellor he blocked spending on equipment for forces.
• The Tories supported the invasion of Iraq but were critical of how the threat was presented, and the handling of the aftermath.
Labour and the Conservatives back Britain's military mission in Afghanistan, where it has 9,500 troops battling the Taliban. The Lib Dems have given critical backing to the mission. However, the Conservatives and the Liberal Democrats accuse Mr Brown of sending troops without adequate equipment, a charge that the Prime Minister denies.
• Labour is committed to military action in Afghanistan and aims to shift the mission to training rather than war fighting, with a suggestion that British troop numbers could start reducing in 2011.
• The Lib Dems say they are 'critical supporters' of the Afghanistan mission and last year called for a change in strategy. They believe a successful strategy would stabilise Afghanistan enough to allow British troops to come home in the next four to five years.
• The Conservatives support military action in Afghanistan. They have pledged to double operational bonuses for troops, and provide university scholarships for the children of service personnel killed.
Britain is one of the six powers dealing with the Iranian nuclear issue. Iran insists its programme is peaceful but the West suspects it wants to build nuclear weapons.
• The Conservatives and Labour back new sanctions on Iran.
• The Lib Dems, who favour a diplomatic solution, say they are ready to back targeted sanctions, but oppose military action.
Labour has seized on Mr Cameron's comment in the first debate questioning the wisdom of Britain giving up its nuclear weapons when 'we can't be certain of the future in China'. David Miliband, Labour Foreign Secretary, has called Mr Cameron's remark an insult to China and urged him to withdraw it.
Labour has had a close relationship with the US, particularly under former Prime Minister Tony Blair. The Conservatives say their relationship with the US would be 'solid but not slavish'. Mr Clegg says over-reliance on the US relationship is not desirable in a multi-polar world.
• Gordon Brown has said the UK-US link remains 'strong and enduring', but has also called for stronger parallel ties between Europe and the US.
• The Tories view the transatlantic connection as crucial, and would seek to deepen links.
• Mr Clegg has insisted Britain must end its slavish and 'embarrassing' devotion to Washington, and focus more on European alliances
Reuters and Press Association