Senior Isis leaders have been forced to accept that they will lose their caliphate in Syria and Iraq and see terrorist attacks in the West as the way forward for jihad, according to foreign fighters who are abandoning the Islamist group as it faces an onslaught in Mosul and an impending attack on Raqqa.

The killings of some of their best commanders, divisions and fear of treachery have contributed to Isis steadily losing territory, according to two Belgian Muslims who recently deserted and fled to Turkey. At the same time, destruction of munitions has led to the group depending more and more on light weapons, suicide bomb cars and IEDs (improvised explosive devices) to try and stem the offensives being launched against it.

“When Daesh [Isis] went into Iraq and took the armour and Humvees from the Iraqi army, it was a big success because it allowed them to move forward very fast. But once the bombing started by the Americans a lot of these armoured cars and Humvees just got smashed; moving around in them just made you a big target,” said Rachid, 27, who used to work as a mechanic in Belgium before his journey to Syria.

“Now the Daesh leaders talk about ribat, which means defending territory, not going forward, so it is a different kind of warfare. Daesh have [surface-to-air] missiles, sure. They have even built their own but how many planes have they brought down? Very few, it is not so easy with modern planes,” he continued. “They still have very good bombmakers and suicide cars are very good because they are effective and really make the enemy afraid. But when the Americans and the Russians started their air strikes these cars were getting blown up before they got to the enemy, so not so effective now and also numbers of people volunteering to be suicide bombers has fallen.

“But you can get people prepared to be suicide bombers in Europe and they can cause much more damage. So, the leaders of Daesh are saying that is where the struggle should take place. A lot of the brothers now feel Mosul cannot be held, Raqqa cannot be held. So, the fight is moving to Europe”.

Mosul battle: Civilians flee ahead of fighting

Despite Belgium appearing to become a base in Europe for Islamist terrorism, with fighters returning from Syria being responsible for murders in Paris and Brussels, Rachid and his Belgian companion, Yasin, claimed to have no knowledge of those attacks and hardly knew those who carried them out.

“They did not hold a majlis [council] to discuss what they were doing. Of course we were not in the rooms with these people when they were deciding what to do,” Yasin wanted to stress. “And you must know that a lot of these attacks have been planned in Europe, in America, with people carrying them out just giving bay’ah [allegiance] to the Sheikh [Abu Bakr al-Baghdadi, the head of Isis]. They are not asking for instructions from Raqaa.”

Both the men, who are of Moroccan descent, said they had gone to Syria after being angered by violent suppression of protests by President Bashar al-Assad’s regime. They had been in contact with other European nationals who were already in the country and found it relatively easy to cross the border from Turkey.

“At the time they were not doing anything much to stop people going to Syria from Belgium. I think that was the case with most of the other European countries as well”, said Rachid. “The European governments were against Bashar, so why would they stop us? I know it’s much more difficult now, but there has been a big drop in foreign volunteers anyway.”

The men had joined Isis, they claimed, after trying other jihadi groups because it was the best at fighting the regime. For Yasin, it was also because “it was the most pure and dedicated”. They claimed disillusionment had set in after witnessing excesses committed by Isis and confessed they were frightened of being killed if they had stayed in Syria.

The accounts given by Rachid, slim and talkative, and Yasin, short, muscular and taciturn, were, at times, self-serving. They had fought on various frontlines such as at the capture of the towns of Manbij, Qalamun and Aleppo but had not, they insisted, taken part in executions and the violent punishments meted out by Isis.

Yasin wanted to qualify: “most people approved of what the Hisbah [the religious police] were doing, because they are Muslim and they believe in sharia. The punishments were harsh, but they made people keep to the law. That was the way it was at the beginning…” Rachid interjected: “But then it became more and more harsh and if people complained they were accused of being apostates, even traitors. They would be punished severely if they protested.”

The two men and a number of other opposition fighters from different groups claim that the Isis leadership feared that the group had been infiltrated by Western intelligence agencies, led by the British. The suspicion and paranoia, they said, stretched to military planning. “If you disagreed with something a commander was saying, making bad decisions, then there was always the risk someone will say, ‘why are you disrupting, are you a spy?’” said Rachid. “Those of us who had volunteered from other countries had to be extra careful. That was not the situation before, but they became more paranoid.”

Yet it was the death of a foreign commander which has been a major loss to Isis, said the two men. Omar al-Shishani, a Georgian-Chechen whose real name was Tarkhan Tayumurazovich Batirashvilli, was reported killed outside Mosul in an air strike last summer. “I know that some people think he may not be dead, but there was real disappointment in Daesh over this when the news came because he was so experienced and was such a brave leader,” said Yasin. “But other commanders have been killed as well, it is a big problem for Daesh.”

Isis is also suffering from loss of revenues as it loses territory, in particular the oil fields it used to control. The group has also made considerable sums from ransoms paid by Western governments for hostages. It has been claimed that the French and Spanish governments paid sizeable sums for the release of their nationals held by jailers led by Mohammed Emwazi, the British jihadist who became known as “Jihadi John”.

The US and UK governments have a policy of refusing to pay ransom and American and British hostages, including the photojournalist James Foley and aid workers David Haines and Alan Hemming were beheaded by Emwazi.

“First of all, we do not approve of those killings; we had nothing to do with it. But they would have been probably freed if money had been paid. Other governments had paid money, everyone knows that, I think a German woman was freed recently, how much was paid for her,” Rachid asked Yasin, who said he had heard that €10m had been paid to an Islamist group linked to Jabhat al-Nusra, an al-Qaeda affiliate which recently changed its name to Jabhat Fatah al-Sham.

“That is a lot less than before, we heard the Spanish paid €30m,” said Rachid. “But the ordinary volunteers do not know what happens to the money. We just got paid, that’s all.” The two men said they received around $60 a month and free housing. Those with families had food and other essentials paid for.

In pictures: Mosul offensive Show all 40 1 /40 In pictures: Mosul offensive In pictures: Mosul offensive A doctor carries an Iraqi newborn baby at a hospital in Mosul, Iraq July 18, 2017. Reuters In pictures: Mosul offensive Iraqi girls play at a yard of a school in Mosul, Iraq July 18, 2017alal Reuters In pictures: Mosul offensive A woman on crutches who is a relative of men accused of being Islamic State militants is seen at a camp in Bartella, east of Mosul, Iraq July 15, 2017. Picture taken July 15, 2017. Reuters In pictures: Mosul offensive A displaced girl, who fled from home carries a doll at Hamam al-Alil camp south of Mosul, Iraq July 13, 2017. Reuters In pictures: Mosul offensive Iraqi federal police members and civilians celebrate in the Old City of Mosul on 9 July 2017 after the government's announcement of the "liberation" of the embattled city. Iraqi Prime Minister Haider al-Abadi's office said he was in "liberated" Mosul to congratulate "the heroic fighters and the Iraqi people on the achievement of the major victory" AFP/Getty Images In pictures: Mosul offensive A picture taken on 9 July 2017, shows a general view of the destruction in Mosul's Old City. Iraq will announce imminently a final victory in the nearly nine-month offensive to retake Mosul from jihadists, a US general said Saturday, as celebrations broke out among police forces in the city. AFP In pictures: Mosul offensive Members of the Iraqi federal police raise the victory gesture as they ride on a humvee while advancing through the Old City of Mosul on 28 June 2017, as the offensive continues to retake the last district held by Islamic State (IS) group fighters. AFP/Getty Images In pictures: Mosul offensive Smoke billows as Iraqi forces advance through the Old City of Mosul on 26 June 2017, during the ongoing offensive to retake the last district held by the Islamic State (IS) group. AFP/Getty Images In pictures: Mosul offensive An Iraqi man wearing the green scarf of the Shi'ite faith kisses an Iraqi Army soldier on safely reaching the Iraqi forces position as Iraqi civilians flee the Old City of west Mosul where heavy fighting continues on 23 June 2017. Iraqi forces continue to encounter stiff resistance with improvised explosive devices, car bombs, heavy mortar fire and snipers hampering their advance. Getty Images In pictures: Mosul offensive A picture taken from the inside of an Iraqi forces armoured vehicle shows residents walking through a damaged street as troops advance towards Mosul's Old City on 18 June 2017, during the ongoing offensive to retake the last district still held by the Islamic State (IS) group. Military commanders told AFP the assault had begun at dawn after overnight air strikes by the US-led coalition backing Iraqi forces. They said the jihadists were putting up fierce resistance. AFP/Getty Images In pictures: Mosul offensive Iraqi Army soldiers advance in a destroyed street after an Iraqi forces airstrike targeted an Islamic State sniper position 17 June 2017 in al-Shifa, the last district of west Mosul under Islamic State control. IS snipers, as well as car and suicide bomb attacks continue to hinder the Iraqi forces efforts to retake the final district. A series of airstrikes by Iraqi helicopter gunships attempted to hit multiple Islamic State sniper positions in al-Shifa. Getty Images In pictures: Mosul offensive An Iraqi soldier frisks a displaced Iraqi man at a temporary camp in the compound of the closed Nineveh International Hotel in Mosul on 16 June 2017 which was recovered by Iraqi troops from Islamic State group fighters earlier in the year. A screening centre set up in the compound's fairgrounds sees a constant stream of Iraqis fleeing the battle for Mosul, awaiting their turn to be checked by the Iraqi forces who are searching for suspected Islamic State (IS) group members. The small fairground lies at the end of a pontoon bridge across the Tigris recently opened to civilians that is the only physical link between the two banks of the river. AFP/Getty Images In pictures: Mosul offensive Iraqis staying at the al-Khazir camp swim in a river near the camp for internally displaced people, located between Arbil and Mosul on 11 June 2017. AFP/Getty Images In pictures: Mosul offensive Iraqi government forces drive on a road leading to Tal Afar on 9 June 2017, during ongoing battles to retake the city from Islamic State (IS) group fighters. AFP/Getty Images In pictures: Mosul offensive An Iraqi policeman carries a poster bearing an image of Mosul's iconic leaning minaret, known as the "Hadba" (Hunchback), on 22 June 2017. AFP/Getty Images In pictures: Mosul offensive Iraqis stand in line to receive food aid in western Mosul's Zanjili neighbourhood on 7 June 2017, during ongoing battles as Iraqi forces try to retake the city from Islamic State (IS) group fighters. Living conditions in Mosul have again deteriorated since the start of the Iraqi government's offensive on the city in October in which they retook a large part of the west of the city. AFP/Getty Images In pictures: Mosul offensive Displaced Iraqis carry lightbulbs and sacks as they evacuate from western Mosul's Zanjili neighbourhood as government forces advance in the area during their ongoing battle against Islamic State (IS) group fighters on 13 May 2017 AFP/Getty Images In pictures: Mosul offensive A member of the Iraqi Counter-Terrorism Service (CTS) flashes the victory gesture as he patrols in western Mosul's al-Islah al-Zaraye neighbourhood on 13 May 2017 AFP/Getty Images In pictures: Mosul offensive Iraqi army soldiers from the 9th armoured division on a truck flash the sign of victory as they drive back from Mosul to the town of Qaraqosh (also known as Hamdaniya) Getty In pictures: Mosul offensive Members of Iraqi forces flash the sign of victory on their vehicle as they advance towards Hammam al-Alil area south of Mosul Getty In pictures: Mosul offensive A member of Iraqi security forces gestures in Hammam al-Alil, south of Mosul, Iraq Reuters In pictures: Mosul offensive Iraqi children, one flashing the sign of victory, greet Iraqi army's soldiers from the 9th armoured division in the area of Ali Rash, adjacent to the eastern Al-Intissar neighbourhood of Mosul Getty In pictures: Mosul offensive Peshmerga forces look at a tunnel used by Islamic State militants near the town of Bashiqa, east of Mosul, during an operation to attack Islamic State militants in Mosul, Iraq Reuters In pictures: Mosul offensive An Iraqi soldier takes a photograph with his phone as his comrade stands next to a detained man, whom the Iraqi army soldiers accused of being an Islamic State fighter, who was fleeing with his family in the Intisar disrict of eastern Mosul, Iraq Reuters In pictures: Mosul offensive Iranian Kurdish female members of the Freedom Party of Kurdistan (PAK) hold a position in an area near the town of Bashiqa, some 25 kilometres north east of Mosul Getty In pictures: Mosul offensive Iraqi families, who fled their homes in Hamam al-Alil, gather on the outskirts of their town Getty In pictures: Mosul offensive Displaced people walk past a checkpoint near Qayara, south of Mosul, Iraq AP In pictures: Mosul offensive Iraqi families who were displaced by the ongoing operation by Iraqi forces against jihadists of the Islamic State group to retake the city of Mosul, are seen gathering in an area near Qayyarah In pictures: Mosul offensive A boy who just fled Abu Jarbuah village is seen with his family at a Kurdish Peshmerga position between two front lines near Bashiqa, east of Mosul, Iraq Reuters In pictures: Mosul offensive An Iraqi child eats a pomegranate upon the arrival of Iraqi forces in the village of Umm Mahahir, south of Mosul Getty In pictures: Mosul offensive People who just fled Abu Jarbuah village sit as they eat at a Kurdish Peshmerga position between two front lines near Bashiqa, east of Mosul, Iraq Reuters In pictures: Mosul offensive A couple who just fled Abu Jarbuah village are escorted by Kurdish Peshmerga soldiers Reuters In pictures: Mosul offensive Women carry a boy over a wall as civilians flee their houses in the village of Tob Zawa, Iraq AP In pictures: Mosul offensive An Iraqi soldier and a civilian ride a motorbike as smoke rises behind them, on the road between Qayyarah and Mosul Getty In pictures: Mosul offensive A member of Iraqi forces, wearing a skull mask, waits at a checkpoint for people fleeing the main hub city of Mosul Getty In pictures: Mosul offensive An Iraqi soldier sits at a checkpoint in an area near Qayyarah Getty In pictures: Mosul offensive Iraqi men prepare food portions for Iraqi forces deployed in areas south of Mosul Getty In pictures: Mosul offensive Iraqi forces celebrate upon the arrival of vehicles bringing food to them Getty In pictures: Mosul offensive Iraqi childen smoke cigarettes upon the arrival of Iraqi forces in the village of Umm Mahahir, south of Mosul Getty In pictures: Mosul offensive A member of Iraqi forces distributes drinks to children in the village of Umm Mahahir, south of Mosul Getty

Rachid and Yasin would face criminal charges and the prospect of lengthy prison sentences if they return to Belgium. The leaders of Isis, they maintained, have their own escape plan and would evade capture or being killed in Mosul and Raqaa. “Look how long it took them to get to Osama bin Laden,” Rashid reminded.