Video report by ITV News Presenter Tom Bradby

It started as protests in Damascus's Old City and the southern city of Daraa over security forces' detention of a group of boys accused of painting anti-government graffiti on their school walls.

Six long and brutal years have since passed - and as the Syria civil war enters its seventh, it has officially outlasted the Second World War.

Little more than three days past between those initial protests in March 2011 and what activists regard as the first deaths of the uprising, when security forces opened fire on a demonstration killing four people.

More than 400,000 civilians - possibly as many as half a million - are believed to have perished since.

This week, the boss of the Red Cross charity said the scale of destruction in Syria is on a level not seen since the last world war.

Little wonder, then, that more than half of Syria's 22.8 million pre-war population have been displaced within the country and across its borders in search of safety.

According to Unicef, six million children in the country now depend on humanitarian assistance and a total of 2.3 million do not have a school.

The former foreign secretary David Miliband has urged the world to "put the humanity back" into the pursuit of peace in Syria.

"The message for the sixth anniversary is that 25 million refugees (worldwide) are 25 million people, and the great danger is that the statistics dehumanise the refugee population," he said.

A child carries manuals distributed by UNICEF volunteers in eastern Aleppo. Credit: AP

He continued: "These are doctors and dentists and business people and housewives and househusbands and people who are really trying to keep their lives together in the way that you or I do, but trying to do so in appalling circumstances.

"And I think that the message on the sixth anniversary of the Syria crisis is that 500,000 lives have been lost. That's not a statistic, that's 500,000 people whose families have been grotesquely affected by this.

"The sixth anniversary is a day to put the humanity back into the conduct of the war and into the pursuit of peace."

500,000 Estimated number of people to have been killed

7.6m Number of people forced out of their homes within Syria

6m Number of children who now depend on humanitarian relief

400 Attacks against medical facilities

International Development Secretary Priti Patel said that the UK had committed £2.3 billion since 2012 to humanitarian assistance for people in Syria and refugee camps in neighbouring countries like Lebanon, Jordan and Turkey.

The aid cash has funded more than 21 million monthly food rations, 6.5 million relief packages, 6.3 million vaccinations and almost 5 million medical consultations, the Department for International Development said.

The efforts, however, of individuals, organisations and governments to help the innocent victims of Syria's civil war have sometimes been in vain.

Aid convoys were attacked in war in Aleppo. Credit: AP

Hospitals were targeted in the battle for Aleppo. Credit: AP

The once rebel-held Ansari neighborhood in eastern Aleppo, Syria. Credit: AP

According to NGO Physicians for Human Rights, there have been 400 attacks against medical facilities since the conflict unfolded and a total of 768 medical workers killed.

Earlier this month, the United Nations detailed in a damning report how serious violations of international laws amounting to war crimes had been committed during the battle for Aleppo last year.

It also condemned "brutal" tactics used by pro-government forces, which it accused of using prohibited chlorine bombs and deliberately starving civilians.

Urging caution as the conflict moves into its seventh year, Mr Miliband added: "This is an extremely complicated region, where external engagement can be very influential and where all sorts of actors are now on the stage.

"It's very important that western countries take careful note of the different players and are very, very careful indeed of the kind of actions that can promote stability or undermine it, and that's something that needs to be central over the next few months."

Key moments in Syria's six-year civil war

2011

March - Protests erupt in Damascus's Old City and the southern city of Daraa over security forces' detention of a group of boys accused of painting anti-government graffiti on their school walls. Four people are killed three days later when security forces open fire on a protest.

June - Police and soldiers in Jisr al-Shughour in north-eastern Syria join protesters they were ordered to shoot. The uprising claims control of a town for the first time before it is retaken by Government forces days later.

August - US President Barack Obama calls on Bashar Assad to resign and orders Syrian government assets frozen.

2012

Summer - Fighting spreads to Aleppo, Syria's most populous city. Rebel fighters seize the eastern half of the city. An estimated one million civilians are forced to flee.

Syrian citizens inspect damaged buildings after airstrikes hit Aleppo. Credit: AP

2013

March - Rebel forces capture Raqqa, a city of 500,000 people.

August-September - A chemical weapons attack in the Damascus suburbs kills hundreds.

October - Syria destroys its chemical weapons production equipment.

2014

February - Two rounds of UN-brokered peace talks in Geneva end without a breakthrough.

June 3 - Syrians in government areas vote in presidential elections. Assad, one of three candidates, wins with 88.7%.

June - IS seizes large parts of northern and western Iraq. In control of around a third of Syria and Iraq, it declares a self-styled Islamic caliphate.

September 23 - The US-led coalition begins air strikes against IS targets.

October - British hostage Alan Henning, a cab driver-turned aid worker from Lancashire, is beheaded by an IS extremist dubbed Jihadi John.

Alan Henning was killed by Islamic State after being captured on an aid mission. Credit: PA

2015

May - IS fighters seize the ancient city of Palmyra.

September 30 - Russia begins airstrikes in support of Assad's forces.

2016

February 3 - Indirect peace talks in Geneva collapse after a few days. The US and Russia announce a partial ceasefire.

April - The ceasefire collapses, bombing resumes and the only road out of eastern Aleppo becomes a death trap.

July - Government and allied forces impose a full siege on eastern Aleppo.

September - A ceasefire negotiated by Russia and the US lasts for a few days, but talks to bring in aid go nowhere, and an airstrike hits a humanitarian aid convoy north of the city.

A ceasefire negotiated by Russia and the US only lasted for a few days. Credit: AP

October - Russia announces it is suspending its airstrikes on eastern Aleppo and designates humanitarian corridors, urging the rebels and residents to leave. The rebels reject the offer, no-one uses the corridors and the UN says it cannot carry out medical evacuations due to security concerns.

November - The Government launches an intensified aerial campaign on eastern Aleppo. Syrian troops and allied forces launch a major ground offensive, rebel defences crumble and thousands flee.

December 14 - A ceasefire, brokered by Turkey and Russia, is announced to allow the evacuation of rebels and civilians, effectively surrendering the city to the government. But it never truly takes hold on the ground and government shelling on the remaining rebel-held sliver continues.

2017