21/11/2013 09:26 GMT | Updated 25/01/2014 16:01 GMT

Sectarian Violence in Syria: What Does It Mean for the Rest of Us?

Sectarian violence in Syria is now threatening more than just the Middle East. Syria's civil war, whose direction at first seemed synonymous with other countries of the Arab Spring, quickly became a full-blown battle of Shia-Sunni sectarianism.

After the Iranian embassy in Beirut was bombed this week, it's clear that these tensions are still strong and spilling over. News organisations were quick to suggest the perpetrators of the attack: Iran funds Hezbollah, Hezbollah fights for Assad, Iran is thus a target of the Syrian opposition. Now all this might seem a little confusing. If I were to ask both Iran and rebel forces on their stance over Israel, I'd probably get a similar response. So why, despite this, are they bombing each other?

Iran, Hezbollah and Assad are all in some way supporters of, or connected to, 'Shia' Islam. The second most popular branch of Islamic faith, its followers are a ruling minority in Syria and hold specific beliefs; termed 'Alawites', they make up estimated at 15-20% of the country's Muslim population.

The Syrian rebels on the other hand, and all others who oppose the aforementioned 'Shia' trio, qualify themselves as part of the more popular 'Sunni' sect, making up 87-90% of Muslims across the globe. This divide has its origins in an early disagreement between Muslims over who should lead the religion after the prophet Mohammed's (pbuh) death.

Over the course of history, this has welded together some stubborn alliances. When Al Jazeera asked whether Tuesday's attack would change Iran and Hezbollah's position on Syria, Joseph Kechichian, a political analyst on the region, wearily replied, "probably not".

The worrying thing is that it's now hard to intervene in such conflicts of ideology without appearing to take sides. During the summer, the West initially made clear whose side they were on, repeatedly sounding the cry for a 'surgical' strike on Assad's weaponry. But after recent reports of the Sunni rebels' command structure floundering, I'm willing to bet they're not so sure anymore.

Radical Sunni groups, such as Al Qaeda, are have been operating alongside the rebels for a while now. And at the same time, sympathetic Brits have been making their own pilgrimage to Syria's warzone, rubbing shoulders with these extremists and effectively becoming radicalised. Such antics have recently been dubbed "terrorist tourism", and have UK intelligence agencies worried.

Not only is it relatively easy for those determined to access Syria, (via a quick Easyjet flight and a midnight dash with a smuggler), but should they ever return to the UK, these chaps are likely to have developed some pretty strong views. As the attack on Iran's embassy shows, soldiers of the conflict have no qualms in taking the fight beyond Syria's borders.

Pre-emptively bombing such potential 'threats' is no longer as straightforward as the drone-strike-politics of Waziristan, Pakistan. It would be strange anyway, if the West, after all their support for the rebels, were to turn around and just start picking them off. Instead, aside from the usual monitoring of questionable individuals, the FCO is bolstering aid by matching money raised by UK charities this winter. Such efforts are promoting awareness of what people can do to help, other than taking up arms in the name of sectarianism.

So I'm not trying to be a scaremonger, but having spent a life of sitting on the fence and now living in the Middle East, all this taking of sides is getting me a bit worried. Fringe Shia-Sunni tensions are already present in London, having made the papers this summer, so I fail to see how the returning terror-tourists are going to help things.

And with the UK's latest dealings with Iran, a Shia majority country, and their indecision over striking Assad, Sunni extremists may already see the UK as having picked the wrong side.