As US and British forces pull out of Afghanistan, further victims of the ‘grave of empires’, Russia is experiencing a mix of satisfaction, exasperation and trepidation.

It has its own bitter memories of the country, after all. In 1979, as a friendly regime was falling back in the face of a mounting Islamic fundamentalist insurgency, Soviet forces rolled into Afghanistan. The idea was that by installing a new leader and mounting a brief show of force, the rebels would be intimidated back into line. Six months, the old men in the Kremlin told themselves, that is all it would take.

And so began a vicious ten-year war that saw the deaths of 15,000 Soviets and hundreds of thousands of Afghans. When the war ended in 1988, it was not because the Soviets had been beaten on the battlefield but because they had been exhausted. Any hope of winning the war depended on a political, military and economic commitment that Moscow simply could not countenance — some generals even talked of deploying a million men.

So too for the United States, and the sight of their withdrawal, similarly exhausted by their own Afghan experience, does provide a degree of Russian schadenfreude, especially for a generation of military officers who remember their own miserable time there.

But also exasperation, because of the sense that the chaos the allies are leaving behind was predictable — and is now at Russia’s doorstep. Foreign minister Sergei Lavrov complained that after the ‘failure of its 20-year-long mission’, Washington was ‘leaving the entire situation open for a force scenario.’

Hence the trepidation: will the anticipated turmoil in Afghanistan spread? The Taleban look to be in the ascendant but will still not find it easy making the switch from insurgency to government, especially in a country riven by ethnic, regional and factional divisions, and where opium warlords have their own lethal agendas.

Already, Russia has closed its consulate in the northern city of Mazar-e-Sharif. There are uncorroborated reports that elements of Zaslon, the special forces unit of the Foreign Intelligence Service, have been sent to beef up security at its embassy in Kabul.

The real concern is that Islamist militants will stir up trouble in neighbouring Central Asia, or even stage cross-border incursions. Tajikistan is especially vulnerable, with a 870 mile-long frontier over which more than a thousand Afghan troops have already fled seeking sanctuary.

Tajikistan has mobilised some 20,000 reservists to reinforce the border but it has also appealed to its allies within the Collective Security Treaty Organisation, a Russian-dominated Eurasian alliance. Russia has a limited military presence in Tajikistan, but of the 6,000 servicemen at its 201st Military Base outside Dushanbe, many are Tajiks who chose to enlist as a way of gaining Russian citizenship. It is now looking increasingly likely that Moscow will bring the base to full operational status and reinforce its contingent there.

After all, what happens in Central Asia doesn’t necessarily stay there. It is not just that it will test Moscow’s claims to being the region’s security guarantor — arguably the last basis for its assertion of Eurasian hegemony. It is also that, given the degree to which the Russian economy depends on cheap migrant labour from the region, the concern is that any upsurges in jihadism could lead to terrorism in Russia and also spread to its own Muslim population.

This is probably a rather exaggerated concern, but not wholly unfounded. Some 10 to 14 per cent of all Russians are Muslims — especially in the North Caucasus where first al-Qaeda and then Islamic State managed to make some inroads into local insurgencies. There have also been terrorist attacks carried out by radicalised Central Asians, including a metro bombing in St Petersburg in 2017 that killed 15 people.

Moscow will do what it can to bolster its Central Asian allies and maintain a cordon sanitaire. It is also maintaining relationships in Afghanistan — the Kremlin talks to Kabul and a range of local warlords — to try and leverage its influence.

But what if all that fails? The spectre haunting Moscow is that one day it might find itself in a situation where being sucked back into Afghanistan, however terrible, becomes unavoidable.