The first audio recording of Isis leader Abu Bakr al-Baghdadi in almost a year has been released by one of the extremists’ news channels in an attempt to show they remain strong even as the fight for the jihadists’ capital of Raqqa reaches its end game.

Much of the 46-minute-long recording is not newsy, just hadiths and quotation of Quranic verse - but references to Russian influence in Syria and the current spat between North Korea and the US has still been triumphantly received by Isis sympathisers as proof that the leader is still alive.

US intelligence has not yet verified the recording but a Defence Department statement on Thursday said that there was no reason “to doubt its authenticity”.

Footage shows Isis schoolgirl Linda Wenzel being captured in Iraq

It comes after multiple claims by Russia and the UK-based monitor the Syrian Observatory for Human Rights - most recently this June – that Baghdadi was killed in an air strike.

The secretive leader has only ever made one public appearance, when he declared the creation of Isis’ caliphate from the Grand Mosque in the Iraqi city of Mosul in July 2014.

“He's a symbolic figurehead, and for that reason he is important, but the group over the last few years has cultivated a cult of the institution of caliphate rather than a cult of personality around Baghdadi,” Charlie Winter, an analyst at the International Centre for the Study of Radicalisation at King's College London, told BBC Radio 4’s Today programme.

“If he goes the organisation will remain and they will just appoint a new caliph,” he added.

In pictures: Isis' weapons factories Show all 11 1 /11 In pictures: Isis' weapons factories In pictures: Isis' weapons factories A mortar round fin manufactured by Isis in Gogjali, Mosul, November 2016 Conflict Armament Research In pictures: Isis' weapons factories Isis rocket components discovered in Gogjali, Mosul, Iraq in November 2016 Conflict Armament Research In pictures: Isis' weapons factories Isis mortars discovered near Karamlais, Iraq, in November 2016 CAR In pictures: Isis' weapons factories An Isis rocket launch frame in Qaraqosh, November 2016 Conflict Armament Research In pictures: Isis' weapons factories A memo from Isis' COSQC on quality control at a manufacturing facility in Gogjali, Mosul, November 2016 Conflict Armament Research In pictures: Isis' weapons factories Electrically-operated initiators manufactured by Isis in forces Gogjali, Mosul, November 2016 Conflict Armament Research In pictures: Isis' weapons factories Isis mortar tubes at a manufacturing facility in Karamlais, November 2016 Conflict Armament Research In pictures: Isis' weapons factories An Isis mortar production facility discovered in Gogjali, Mosul, in November 2016 Conflict Armament Research In pictures: Isis' weapons factories An Isis weapons manufacturing facilities near Mosul in November 2016 Conflict Armament Research In pictures: Isis' weapons factories Stocks of French-manufactured Sorbitol, Latvian potassium nitrate and Lebanese sugar at an Isis weapons factory in Iraq Conflict Armament Research In pictures: Isis' weapons factories A destroyed Isis weapons facility in Qaraqosh, Iraq, November 2016 Conflict Armament Research

While in the short term the Baghdadi address will boost morale for Isis fighters struggling to hold on to the last neighbourhoods of Raqqa, it will do little to change the fact Isis’ once-mighty caliphate is almost completely vanquished.

The mainly Kurdish-Arab US-backed Syrian Democratic Forces (SDF) have faced fierce counter attacks in the last 24 hours, but Isis’ grip on the city is all but gone. Most commanders and other important figures have already retreated into the desert, leaving sniper units and improvised explosive devices (IEDs) to hinder the SDF’s advance.

In Deir Ezzor, in the eastern desert, the Syrian government has denied reports that militants managed to regain control of the highway to Palmyra. Even if Isis did retake the road, however, they are just prolonging the inevitable: the siege around the city was broken earlier this month, and the remaining fighters cannot hold out against both Russian and Syrian air power.

As the jihadists’ front lines collapse, the propaganda offerings have increased, an effort to prove that Isis is still dangerous as it morphs from a land-holding force to an insurgency group.

As well as the Baghdadi recording, this week alone Isis has claimed to be holding two Russian soldiers hostage in the countryside of Deir Ezzor and released a horrific new video showing a clearly drugged teenage suicide bomber taught how to detonate explosives before he drives off to kill himself and Syrian soldiers.

Liberated from Isis, women burn their burqas and men shave off their beards

The grisly content, designed to inflict fear, still betrays the wider truth: losing men, Isis recently took the step of forcibly conscripting male civilians for the first time, and encouraged women and children of the caliphate to join the fighting.

Isis’ desperation will be of little comfort for the civilians still under their control, who must face these new threats as well as the consequences of US and Russian air strikes.