EU arms to Syria: what, how and if

But if the talks - due to start in Geneva this month - fail, they will have some hard choices to make.

Defence analysts say what the rebels really need are shoulder-fired anti-aircraft and anti-tank missiles.

They listed four Western-made anti-aircraft models - the Stinger, the Mistral, the Blowpipe and the Starstreak - as potential choices.

They also listed three Western anti-tank models - the Carl Gustav, the Panzerfaust and the Panzerabwehrrichtmine - as options.

They said Britain and France might instead buy Russian-made equivalents on the open market.

The Russian choices include the Strela and Igla anti-aircraft missiles and the RPG7, RPG18 or RPG29 anti-tank weapons.

"Even low-tech anti-aircraft systems would make Assad's forces keep their distance. They would no longer have the free run of the battlefield," Edward Hunt, from British defence consultancy Janes, told this website.

"Syria uses helicopters to rapidly deploy crack units from east to west or vice versa to hit back at rebels. Shoulder-fired missiles would make this impossible. The ability to shoot down helicopters means the Syrian military would be confined to moving its troops using [ground] convoys," Jonathan Eyal, from the UK military think tank Rusi, noted.

It might make a big difference whether they send Western or Russian material.

They would have to train rebels to use Western equipment and keep them supplied with ammunition and spare parts.

But Assad soldiers-turned-rebels are familiar with Russian weapons and can loot ammunition from the Russian-armed regime.

Eliot Higgins, who writes the Brown Moses blog on Syria, told this website the rebels have already been using high-tech Russian anti-tank weapons "in increasing numbers over the last nine months, in line with increasing captures of ammo dumps and bases."

Russian arms are also better for propaganda purposes.

"You don't want to send material which is easily recognisable as your own," Jane's Hunt said.

"You don't want the Syrians to show a British rifle on TV and say: 'Look. This is what killed this poor boy's mother.' If you're trying to keep the moral high ground, you don't want your bullets showing up in the bodies of civilians," he noted.

Otfried Nassauer, from the German arms-control NGO Bits, added that Western weapons are harder to get back once a conflict ends.

The US supplied Stingers to anti-Russian guerrillas in Afghanistan in the 1980s. They cost $30,000-or-so brand new. But when the US tried to buy them back for more than $50,000 a piece, many Mujahideen fighters preferred to "keep them under their bed."

"Whoever has one is perceived to be very important," Nassauer said.

Opinion is divided on the Western/Russian-made question.

Rusi's Eyal said: "Time is a factor. In practice it would be cumbersome to rely on Russian supplies in large quantities. What happened in Libya is that countries [who supplied rebels in the 2011 Libya war] rustled up whatever they could get their hands on quickly from their own arsenals."

He added that the nature of the Syria war makes spare parts irrelevant.

"Spare parts are meaningful for an organised force with a logistics back-up line to service weapons and bring them back into battle. There's no such thing here. The rebels use weapons until they jam and then throw them away," he said.

The question of which models of weapon to ship is also key to the biggest problem in the Anglo-French plan - the risk of proliferation.

The main rebel group - the Free Syrian Army, described as "moderates" by British and French diplomats - has a chain of command and has pledged to create democracy.

But if Islamist rebel groups - such as Ahrar al-Sham, Jabhat al-Nusra or al-Qaeda - get their hands on Western equipment they might use it against Western allies, such as Israel or Jordan. Individual extremists might also smuggle it back to Europe for terrorist attacks.

Top-end anti-aircraft missiles - such as modern Stinger or Igla-type models - are a threat to the Israeli air force.

Top-end anti-tank weapons, such as RPG29s, are a threat to Israeli tanks.

The anti-aircraft missiles also pose a danger to civilian planes on low flight paths or on take-off and landing.

Russian media reports that two rebel-fired missiles narrowly missed a passenger jet carrying 159 tourists from Sharm el-Sheikh in Egypt to the Russian city of Kazan in April.

If Britain and France go ahead, analysts expect them to ship arms via the Jordanian-Syrian border.

They would fly them in using military cargo planes or charter civilian aircraft and use ground forces to control who gets what.

"Some special forces would have to be deployed in Syria to ensure the material gets to the right people. You can't just dump it on the border and hope for the best," Rusi's Eyal said.

The Brown Moses blogger noted that rebel groups "trade and sell" arms to one another once they get them, however.

Meanwhile, even Israeli intelligence has trouble telling who is who.

Alon Ben-David, a defence expert at Israel's Channel 10 broadcaster, told this website: "Israeli intelligence has tried to build a picture of who the rebels are. But it's a riddle. Every town has its own armed gangs which act independently of each other and which are impossible to identify."

He said: "Just because you meet a rebel commander who speaks good English and who doesn't have a beard doesn't mean you know who he really represents."

Rusi's Eyal added: "You could end up creating a parallel army … You could end up creating another Taliban [an anti-Western force in Afghanistan and Pakistan]."

Amid the doubts on what to send, analysts wonder if Britain and France will really ahead no matter what happens in the Geneva talks.

For Eyal, the whole thing is "a bluff" designed to scare al-Assad to make concessions.

For Nick Witney, an analyst at the British-based ECFR think tank, "they are hoping against hope that the Geneva talks are a success so they don't have to follow through."

For Christopher Philips, from British think tank Chatham House, they are "posturing" on the world stage.

He said Britain and France - former colonial powers in the Middle East - "have delusions of grandeur" and a "misplaced sense of their own importance."

Philips noted that despite its tough talk, there are "divisions" inside the British foreign office on whether to send arms.

"It's very questionable if they will send modern anti-aircraft missiles … The quantity and quality of weapons they might supply is negligible compared to what's coming in from [al-Assad's allies] the Russians and the Iranians. So it wouldn't solve anything. It would just be flooding the region with arms," he said.

Julian Barnes-Dacey, another ECFR pundit, said EU countries should start talking to al-Assad and to Iran instead of playing "diplomacy-lite" and "intervention-lite."

"If they are going to intervene militarily, they should go in much more heavily, which they are clearly not willing to do," he said.

Israel's Ben-David agreed.

"If they really want to help, they should create a safe zone in Syria where they can train the rebels and from which rebel forces can come out and fight the regime in an organised way," the Channel 10 analyst said.