The calculation, the result of a five-month UN project to cross-reference names of the dead, suggests that previous analysis of the carnage caused by almost two years of protests, repression and fighting issued by opposition groups was too conservative.
Even the new figure was likely to be an underestimate, the UN high commissioner for human rights suggested, as it ignored incidents with incomplete accounts of victims and could not include those who had been "disposed of" secretly.
The Syrian war is now twice as bloody as that which put an end to the regime of Col Muammar Gaddafi in Libya last year, despite – or as many critics will now start to say because of – the latter's involvement of concentrated Nato air power.
John McCain, the former US presidential candidate who has urged US President Barack Obama to intervene in the conflict, referred to the figures on his Twitter account and said the president's policy was no longer "leading from behind" but "waiting from behind". The UN high commissioner, Navi Pillay, said: "The failure of the international community, in particular the Security Council, to take concrete actions to stop the bloodletting shames us all. Collectively, we have fiddled at the edges while Syria burns."
From the beginning of the uprising – usually dated to the first repression of protests in the city of Deraa on March 15, 2011 – it took nine months for the number of dead to reach 5,000. The next 5,000 were killed in the subsequent five months, including hundreds in February in the shelling of rebel districts of Homs, the first major siege. From then on, roughly 5,000 people have died every month.
Ms Pillay said the new study had cross-referenced names put out by seven sources and eliminated overlaps to come up with a list of 59,648 dead by November 30.
The bloodshed in Syria continued yesterday, most notably when a government air strike in the eastern Ghouta district of Damascus province hit a petrol station, killing possibly up to 50, according to activist groups.
Fighting also continued around Aleppo airport, while rebels launched a third major attack on the airbase at Taftanaz. (© Daily Telegraph, London)