After six years of fierce fighting and with hundreds of thousands dead, the Syrian civil war finally appears to be settling down. The country is now divided into various pockets of influence, with Turkish-backed rebels in the north, US-backed Kurdish forces and their allies in the east and the Syrian regime and its Iranian-backed militias in the centre and the capital, Damascus. This now gives Iran, with the influence it already has in Lebanon and Iraq, a sphere of authority stretching from Tehran to the Mediterranean Sea.

The spread of Iranian influence in the region is largely a result of the country's ability to capitalise on the tumultuous recent history of the Middle East. The last few years of bloodshed have created a vacuum which Iran has willingly filled. In Iraq, the Popular Mobilization Units – a group of mostly Shia militias that are part of the Iraqi government’s forces (and who are trained by Iranian advisers) play a significant role in the war against Isis and in controlling liberated areas. In Lebanon, Hezbollah - which is allied with Iran - has seats in the country's parliament and plays a major role in Lebanese politics; it has also sent thousands of its fighters to bolster Bashar al-Assad’s regime in Syria. The Iranian Revolutionary Guard Corps has also recruited thousands of Afghan and Pakistani Shia to fight in Syria in a unit called the Fatemiyoun Division. Iranian-backed militias have also helped prop up Assad's regime.

While the Syrian war may now be quietening down, none of these Iranian militias will disband any time soon. Instead, it seems likely that at least some of them will morph into an outfit similar to Hezbollah – an armed political party with extra-territorial ambitions. Iran is also alleged to be constructing military bases in Syria and Lebanon. Israeli Prime Minister Benjamin Netanyahu warned this week that 'Iran is busy turning Syrian into a base of military entrenchment'.

Other states in the region have read the tea-leaves and are seeking to co-operate with a rising Iran. Qatar is close to Tehran and Turkey has recently hosted high level delegations from Iran. But none of these closer ties can gloss over the fact that Iran’s role is fundamentally destabilising.

Shia militias are useful for getting rid of Isis's jihadists from Iraq. But in the areas around Mosul that they have liberated, the lack of stability remains palpable. Many Iraqis have fled to the autonomous Kurdish region, first to avoid Isis and now to escape the militias. In Syria, the war has left empty shells of cities and the many millions of refugees who fled will not want to return home to states controlled by sectarian militias. In Lebanon, hostility is growing to Syrian refugees; and the 1.4million refugees who escaped to Jordan are a big strain on the country's economy.

If Iran is allowed to entrench its position across the Middle East, it will not only be Israel that will find itself threatened; a new round of conflict inevitably becomes more likely. The picture of a post-Isis Middle East should be a positive one free from the cancer of extremism. Unfortunately, the increasing role of Iran means it may be a bleak one instead.