Timeline: UK's road to action in Libya

The UK's role in the run-up to military action against Colonel Muammar Gaddafi's regime in Libya.

BACKGROUND: Libya gains independence from Italy in 1951. In 1969, 27-year-old Muammar Gaddafi seizes power from King Idris in a bloodless coup. Under Gaddafi's dictatorial rule, Libya becomes embroiled in frequent confrontations with the West. In 1988, it is blamed for the Lockerbie plane bombing but eventually returns to the diplomatic fold after renouncing weapons of mass destruction. In 2009, Lockerbie bomber Abdelbaset Ali al-Megrahi is freed from jail in Scotland on compassionate grounds and returned to Libya. His release and return to a hero's welcome causes a storm of controversy.

JANUARY 2011: A wave of popular uprisings sweeps the Arab world, starting in Tunisia, with the ousting of longtime President Zine El Abidine Ben Ali, followed by the removal of Egyptian President Hosni Mubarak Unrest spreads to other Arab nations, including Bahrain, Yemen, Oman and Libya.

17 February: Libyan protesters start demonstrating and security forces use snipers and live fire in a tough crackdown.

21 February: UK Prime Minister David Cameron, on a tour of the Middle East, condemns violence by the Gaddafi regime as "appalling and unacceptable" - and tells UK citizens to leave Libya if they can. Foreign Secretary William Hague is criticised for claiming Col Gaddafi has already fled to Venezuela, after unconfirmed reports that turn out to be incorrect.

22 February: Col Gaddafi vows to fight to his "last drop of blood" during a state television broadcast. UK announces plans to charter planes to evacuate stranded Britons.

23 February: Reports start coming through of British oil workers stranded in the desert, running out of water and desperate to be rescued. David Cameron, on a visit to Qatar, calls for UN action on Libya.

24 February: David Cameron has said he is "incredibly sorry" for the government's handling of the evacuation of British nationals from Libya, which is finally getting under way. He also says Col Gaddafi would face "consequences" for his actions and that "no options" should be ruled out if internal repression in Libya continues. US President Barack Obama denounces the violent crackdown by the Libyan authorities on peaceful protesters as "outrageous and unacceptable".

25 February: British citizens arriving back at Gatwick airport speak about a "disastrous" operation to evacuate them from Libya. David Cameron says the government "will do everything it can" to evacuate up to 500 Britons left in Libya. He vows to investigate whether the Libyan regime has committed "war crimes" during its crackdown on protests and says the UK will push for Libyan assets abroad to be frozen and a travel ban to be imposed on senior figures in the regime.

26 February: RAF Hercules planes transport 150 British oil workers from desert locations south of Benghazi in Libya to Malta. The last UK government-chartered plane departs the capital, Tripoli, for London Gatwick. The UN Security Council meets to consider an arms embargo, travel ban and asset freeze on the Gaddafi regime. Barack Obama says the Libyan leader should step down and leave the country.

28 February: David Cameron reveals he has asked the Ministry of Defence to "work with our allies on plans for a military no-fly zone", in a Commons statement on his trip to the Middle East. He also confirms the freezing of Col Gaddafi's British-held assets and those of his family, the withdrawal of their diplomatic immunity and an export ban on Libyan banknotes, which are printed in Britain.

2 March: Mr Cameron is forced to defend the no-fly zone plan after US Defence Secretary Robert Gates dismisses the idea as "loose talk" and says it could only be created after an attack on Libya. The PM faces claims he is isolated internationally, but insists it is right to consider all the options, including military ones.

3 March: The director of the London School of Economics (LSE), where Gaddafi's son Saif studied, resigns over the university's links to the family. William Hague insists the UK is "absolutely in line" with the US in preparing plans for a possible "no-fly zone" and the the international community realises it is only a "contingency" plan.

4 March: Six members of the UK's elite special forces squadron the SAS are captured and detained as they arrive at an agricultural compound in Benghazi. The SAS members are thought to be part of an eight-strong "diplomatic team" sent to the area to make contact with rebel leaders.

6 March: The UK diplomatic team. include the six SAS members, are released by anti-Gaddafi rebels. The botched operation comes in for heavy criticism in the British press, where it is portrayed as a humiliation for the UK. As Libya lurches towards full civil war, Defence Secretary Liam Fox admits that the country could be split in two - but rules out sending UK land forces there.

7 March: William Hague says more UK diplomats may be sent to Libya despite an SAS-escorted team being captured by rebels.

8 March: Labour accuses the government of "serial bungling" over the situation in Libya, following the botched SAS mission.

9 March: David Cameron is forced to defend William Hague in the Commons, saying he is an "excellent" foreign secretary after Labour leader Ed Miliband criticises the botched SAS mission, Mr Hague's claim that Gaddafi had left Libya and the "fiasco" over the evacuation of British citizens. The PM says the UK is leading the way in the push for a no-fly zone. The UK and France are working on a UN resolution for a no-fly zone but the US warns it must be a UN decision with wide international support.

10 March: Gaddafi's security forces detain and beat up members of a BBC team which was trying to reach the strife-torn western city of Zawiya. William Hague and his German counterpart urge the European Union to explore ways of imposing more sanctions on Libya. Mr Hague claims there is "growing support" for a no-fly zone in the Arab world, as the UK and France seek to build support for the UN to draft a resolution urging an air exclusion zone.

11 March: The PM denies being frustrated that EU leaders at a summit had not backed a possible no-fly zone, saying they had agreed to examine "all necessary options", but adds that "Europe needs to seize and shape this moment".

12 March: The Arab League backs the idea of a no-fly zone, while the EU and NATO continue to sit on the fence.

14 March: Mr Cameron insists imposing a no-fly zone over Libya is "perfectly deliverable" - and denies he is having trouble convincing other EU leaders, with the exception of French President Nicolas Sarkozy, of the need for one.

15 March: Col Gaddafi's troops begin bombing the eastern city of Ajdabiya to retake it from Libyan rebels. G8 foreign ministers meeting in Paris warn the Libyan leader he could face "dire consequences" but fail agree to a no-fly zone. Germany and Russia are said to oppose the British and French plan. The UK, France and Lebanon table a draft United Nations resolution which would impose a no-fly zone and other sanctions.

16 March: The UN Security Council starts debating a no-fly zone. UN Secretary-General Ban Ki-moon calls for an immediate ceasefire by Libyan authorities and rebels. Protesters climb on to the roof of the Libyan embassy building in Knightsbridge, central London.

17 March: The UN Security Council approves a resolution authorising a no-fly zone and "all necessary measures" to enforce it in order to protect civilians under threat of attack from the Libyan regime. The resolution is backed by 10 Security Council members, with five abstentions.

18 March: RAF warplanes are deployed to the Mediterranean in preparation to enforce a no-fly zone. The Gaddafi regime responds by announcing an immediate ceasefire. Rebels report that Col Gaddafi's forces are continuing to bombard the opposition-held cities of Misrata and Ajdabiya. President Obama warns Col Gaddafi that the terms of the UN's demands are "not negotiable". Labour leader Ed Miliband gives his full backing to military action.

19 March: Mr Cameron heads to Paris for an emergency summit in Paris attended by world leaders. The PM pledges "the time for action has come". Countries including Canada, Denmark, Spain and Norway are sending planes, while Italy said it would permit the use of air bases such as Sigonella in Sicily and Aviano in the north to launch sorties. Speaking outside Downing Street, Mr Cameron reveals that British forces are in action over Libya. The Ministry of Defence reveals a British submarine has fired a number of Tomahawk missiles at Libyan air defence targets.

20 March: British forces maintain the bombardment of Libya for a second night in succession, firing Tomahawk missiles at air defence targets. The attack comes shortly after Libya's authorities announce a ceasefire, which is greeted with suspicion in London and Washington. RAF Tornado GR4 ground attack aircraft pull out of an attack after civilians are spotted in the target area. David Cameron says all military attacks on Libya will be "fully consistent" with the United Nations mandate, as he faces pressure to clarify whether Col Gaddafi himself could be a target.

21 March: The House of Commons approves the military action by 557 votes to 13. The head of the UK armed forces, General Sir David Richards, says targeting Col Gaddafi is "not allowed under the UN resolution". Defence Secretary Liam Fox had told the BBC it was something that was "potentially a possibility".

27 March: Nato takes control of the whole military operation in Libya - the US had agreed to lead enforcement of the UN resolution initially, but had made it clear it wanted a limited role and would hand over responsibility as soon as possible.

29 March: More than 40 foreign ministers, international organisations and observers meet in London to discuss the next steps of the mission, while, in Libya, pro-Gaddafi forces intensify attacks on rebels, driving them back.

30 March: Libyan Foreign Minister Moussa Koussa arrives in Britain, saying he no longer wants to work for Col Gaddafi's regime - Scottish prosecutors ask to question him about the 1988 Lockerbie bombing. Five Libyan diplomats are expelled from the UK as Foreign Secretary William Hague says they could pose a threat to UK security. David Cameron says the UK is not ruling out providing arms to the Libyan rebels in "certain circumstances".

7 April: Rebels in eastern Libya say their forces have mistakenly been hit in a Nato air raid. Initially a Nato commander refuses to apologise, saying they had not been aware the rebels had tanks. Foreign Secretary William Hague says mistakes happen and Nato should be ready to apologise for the deaths. Nato says it strongly regrets the loss of life.

12 April: UK Foreign Secretary William Hague and his French counterpart, Alain Juppe, say Nato must do more to destroy the heavy weaponry used by pro-Gaddafi forces in Libya. The head of Nato operations in Libya, Brig Gen Mark Van Uhm, says Nato is doing well "with the assets we have". Moussa Koussa leaves the UK for Doha.

13 April: As pro-Gaddafi forces continue to attack the rebel-held city of Misrata, William Hague says an international fund could be set up to provide financial support for Libyan rebels while David Cameron says the UK will provide body armour to opposition forces.

15 April: David Cameron, US President Barack Obama and French President Nicolas Sarkozy write a joint letter to The Times, the International Herald Tribune and Le Figaro. They say there can be no peace in Libya while Col Gaddafi is in power and allowing him to remain would "betray" the Libyan people. One Tory MP says it marks a "significant shift" in policy and, along with two fellow Conservatives, says Parliament should be recalled to debate the mission.