Just when it seems the Syrian war cannot get more complex, it does. In the skies above the Mediterranean, Syrian missiles shoot down an allied Russian surveillance plane after mistaking it for an Israeli bomber. In the Black Sea resort of Sochi, the Russian and Turkish presidents produce a plan for Turkey to use its control of part of Idlib province to disarm the worst jihadi extremists, including Chechens, Uighurs and other foreigners, as well as homegrown Syrian fanatics.

Two points stand out. One is the proliferation of outside interference in what began in 2011 as a purely Syrian campaign for reform. The other is the central and indispensable role that Russia now plays. On Syria’s south-western flank, it deploys military police near the Israeli-occupied Golan so as to prevent pro-Iranian militias from moving up and provoking Israeli forces. It turns a blind eye to Israeli air attacks on Iranian advisers in Syria. Only now with Monday’s loss of a Russian plane does it give the Israelis a public dressing-down for creating the confusion that led to the missile mistake.

Russia’s relationship with Turkey is equally multifaceted. It condemns Turkey’s occupation of northern Syrian territory, including parts of Idlib, but uses Turkey’s presence to demand that Turkey disarm the jihadis it once supported there. Whether Monday’s Sochi agreement will be implemented remains to be seen. Turkey has made earlier promises to tackle the extremists that have come to nothing.

In a separate part of Idlib, Syrian government forces and Russian aircraft are still massing for an assault on other anti-Assad fighters. Here the outside players include Britain, France and the US. They have been mounting a vigorous campaign to prevent a Russian bombing onslaught. While their motives are in part humanitarian, since heavy bombing is bound to cause death and displacement on a massive scale, their calls for a ceasefire are tainted with less honourable motives. They are designed to delay the success that the Syrian army and its Russian allies are about to achieve by regaining control over the last rebel-held region in the Syrian heartland.

Britain, France and the US, along with the Gulf Arab monarchies, have been intimately involved in Syria’s civil war since the uprising against Assad was militarised in 2012. They have aided and financed rebel fighting groups, including jihadi extremists. Calling for ceasefires is a device for helping the rebels rather than the civilians they rule, often in brutal fashion.

Facebook Twitter Pinterest ‘It will be hard to accept that Russian intervention has been broadly positive by bringing the war to an end’. An airstrike near Idlib, Syria. Photograph: AP

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There is a far better way to protect the 2 million or more civilians now huddled in Idlib, many in makeshift camps and other deplorable conditions. It is to find a political settlement under which the rebels surrender. The Syrian government has negotiated more than 100 surrender pacts with various rebel groups over the past two years. Described euphemistically as “reconciliation agreements”, they have permitted thousands of rebels to leave besieged areas. Most have moved to Idlib. Eager to reassert government control, Syrian forces even allowed the rebels to take their rifles and side-arms with them and be transported in government buses.

Thousands of family members and other civilians have gone with the armed fighters, which is why Idlib is now so full of displaced people. But thousands of other Syrians have taken advantage of the reconciliation deals to start rebuilding their homes. They would rather live under Syrian government control than remain in towns and villages at war. The Syrian conflict was never a simple binary struggle between supporters and opponents of Assad. Millions of Syrians had little or no faith in either side but deplored the militarisation of what had started as a non-violent uprising and became a proxy war in which outside states used Syria as a battleground for their own interests.

While Turkey is involved in areas of Idlib run by Hayat Tahrir al-Sham (HTS) – formerly Jabhat al-Nusra, an affiliate of al-Qaida – other parts are under the sway of fighters of Ahrar al-Sham and Noureddine al-Zinki, two groups with whom western special forces have had links. There is also the group known as the White Helmets, who are still on the British, French and US payroll.

Russian planes have been dropping leaflets urging the Idlib rebels to surrender. As happened in eastern Aleppo two years ago, there are reports that rebels punish people who pick up and distribute the leaflets or spread the message that it is better to make peace than go on with a fruitless war. Even at this late stage, the rebels have not given up the hope of a US-led bombing campaign on Assad’s headquarters in Damascus.

Another rebel message is that anyone who surrenders, whether fighter or civilian, will be detained or killed by Syrian forces. The idea that the Syrian authorities would kill civilians who return to government control makes little sense. But even where there are legitimate fears of reprisals, the dangers inherent in carrying on the conflict will inevitably be greater.

Nevertheless, the Syrian government should announce loudly and clearly that amnesty will be given to all of Idlib’s surrendering rebels, provided they have not been part of Islamic State or HTS.

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They will not even be conscripted into the Syrian army (as happened under previous deals), since the government will not need so many troops now that the war is almost over. In return, the British, French and US governments should urge their proxies not to obstruct surrender deals.

It will be hard for many Syrians to admit that the anti-Assad revolution has failed, but denying reality only condemns Syria to more months of suffering. It will be hard for western governments to accept that Assad has won after seven years of demanding that he resign. It will also be hard to accept that Russian intervention has helped bring the war to an end.

The war’s most-repeated cliche is the phrase that Assad has been killing his own people. But that merely underlines that this seven-year-struggle is a civil war in which, by the same logic, the rebels have also been killing their own people. Western governments bear partial responsibility for the carnage. By taking the right course over Idlib, they can begin to make amends.

• Jonathan Steele is a former Guardian foreign correspondent