Syria conflict: UK pledges extra £100m
The UK has pledged an extra £100m to tackle the plight of millions of Syrians affected by civil war.
International Development Secretary Justine Greening made the commitment to the UN's latest crisis appeal at an international "pledging conference for Syria" in Kuwait.
She said the scale of suffering caused was "hard to exaggerate".
The government said the £600m now pledged was "three times its response to any other humanitarian crisis".
Ms Greening said: "Women and children are vulnerable to brutal violence and some have lost everything."
The world "cannot ignore what is happening to the Syrian people", she added.
"Britain is determined to play its role in helping the 11 million Syrians who continue to suffer as a result of this crisis.
"As the situation grows worse, the international community needs to make sure the UN has the resources it needs to help these people."
The Department for International Development (DfID) said the new funding would "help the UN meet critical humanitarian needs including schooling for Syrian children".
The US has promised $380m (£231m) in new contributions while conference host Kuwait has pledged $500m (£204m).
A DfID spokeswoman said the previous "largest humanitarian response" from the UK government was £200m for the victims of the 2011 drought in the Horn of Africa.
Some £134m was pledged in response to the Pakistan floods of 2010 while £140m of support was given following the 2004 Indian Ocean tsunami.
Last week, Deputy Prime Minister Nick Clegg responded to Labour pressure to admit 400-500 Syrian refugees by telling MPs the UK had accepted "about 1,500" asylum seekers from Syria.
"We have accepted hundreds upon hundreds of individual asylum seekers from Syria, under our international asylum obligations," he said.
But Amnesty International criticised Mr Clegg for conflating asylum seekers who have made it to the UK with people in refugee camps in the Middle East.
It followed calls from politicians including Conservative minister Lord Howe, UKIP leader Nigel Farage and former Lib Dem leader Menzies Campbell to consider taking refugees fleeing the Syrian civil war.
Conservative chairman Grant Shapps has told BBC News that Britain was making a large financial contribution and can "hold its head up high".
Meanwhile, UN Secretary General Ban Ki-moon, speaking at the donor conference, said half of Syria's population - "nearly 9.3 million individuals, urgently need humanitarian aid".
It comes after the UN's World Food Programme has said there are reports of malnutrition in areas of Syria either besieged by government forces or cut off by continuing fighting between rival rebel factions.
It said children were being caught up in the fighting and urged greater access for aid agencies.
Syria's refugee crisis has grown steadily since the start of 2012 and accelerated quickly last year.
The UN says about 6.5 million are now displaced inside Syria, with more than 2.3 million registered refugees living across the region in countries like Lebanon, Turkey, Jordan and Iraq.
About 20% of these refugees live in camps - the rest have found shelter in other communities.
Syria's opposition remains deeply divided and there has recently been heavy fighting between rival factions.
The UN says more than 100,000 people have died since the Syrian uprising against President Bashar al-Assad began in March 2011.