What Persuaded PM To Seek Second Syria Vote?

MPs are on the brink of deciding whether to back military action against Islamic State targets in Syria, with a vote on Wednesday.

But how have we got to this point?

:: August 2013

More than 1,400 people are killed in an attack in Damascus - and the UN finds "clear and compelling evidence" chemical weapons were used.

The incident sparks calls for military action against Bashar al Assad, who remains in power in Syria to this day despite almost five years of civil war.

However, British MPs vote against military action, handing a humiliating defeat to David Cameron.

:: 2014

Islamic militants seize territory in Iraq and Syria, exploiting unrest in the former and the civil war in the latter.

The militants later declare a "caliphate", or Islamic state, and change their name to reflect this.

The terrorists begin beheading Western hostages, releasing a series of gruesome propaganda videos.

Britons David Haines and Alan Henning and US citizens James Foley, Steven Sotloff and Peter Kassig are murdered by the militants.

:: August-September 2014

Barack Obama authorises airstrikes in Iraq to slow IS gains.

A month later he launches similar action in Syria along with a number of Arab countries as part of a "steady, relentless effort" to root out the extremists.

At the end of September, the UK joins the bombing campaign in Iraq, with RAF planes launching strikes from a base in Cyprus.

However, military action in Syria remains off the table.

:: Early 2015

IS brutality - and its hold on swathes of Iraq and Syria - continues unabated.

Japanese nationals Haruna Yukawa and Kenji Goto are killed, while Jordanian pilot Moaz al Kasasbeh is burned alive.

:: June 2015

A lone gunman believed to have been devoted to Islamic State kills 38 people during a beach massacre at Sousse in Tunisia.

Thirty of those shot dead by Seifeddine Rezgui are British.

:: August-September 2015

RAF drones - which had previously been deployed over Syria to gather intelligence - take out two British nationals in Syria without Commons approval.

Mr Cameron tells Parliament the strikes were "an act of self-defence" - and that those killed were planning an attack in the UK.

The Britons are named as Reyaad Khan, from Cardiff, and Ruhul Amin, from Aberdeen.

A third UK citizen, Junaid Hussain, is taken out by a US airstrike six days later.

The Prime Minister insists it is not an expansion of British involvement in the region - but he suggests there is a case for doing so.

:: 13 November 2015

Islamic State terrorists kill 130 people in a series of coordinated attacks in Paris.

The second hit on the city in less than a year prompts a Europe-wide manhunt and a number of security alerts across the continent.

:: 16 November 2015

Mr Cameron reveals the UK's intelligence services have foiled seven attacks on British soil in the last year.

:: 20 November 2015

Following an appeal from French President Francois Hollande, the UN Security Council passes a resolution calling on members to redouble their efforts to defeat IS.

:: 26 November 2015

The Prime Minister outlines his case for expanding UK airstrikes from Iraq to Syria.

He says: "The threats to our interests and to our people are such that we cannot afford to stand aside and not to act.

"Throughout Britain's history we have been called on time and again to make the hardest of decisions in defence of our citizens and our country. Today one of the greatest threats we face to our security is the threat from Isil (IS).

"The longer Isil is allowed to grow in Syria, the greater the threat it will pose. It is wrong for the United Kingdom to subcontract its security to other countries, and to expect the aircrews of other nations to carry the burdens and the risks of striking Isil in Syria to stop terrorism here in Britain."

:: 30 November 2015

Jeremy Corbyn indicates Labour MPs will be given a free vote on military action in Syria as Mr Cameron announces the one-day debate will take place on Wednesday.