Sources told The Times of a rising threat from the terror group and Defence Secretary Michael Fallon confirmed there has been a resurgence of al-Qaeda in Afghanistan, meaning Britain is forced to keep troops on the ground in the country.
Sir Fallon said Al-Qaeda posed a ‘very direct threat’ to the UK and Europe.
The new charge of terror is believed to be led by the group’s former leader Osama bin Laden’s son, who has recently issued audio messages aimed at challenging ISIS’ dominance.
Secretary of State for Defence, Michael Fallon (front) said Al-Qaeda posed a ‘very direct threat’ to the UK and Europe
Hamza bin Laden is now thought to be 25 years old and living in Pakistan but he has not been pictured since he was younger.
Former director of operations at MI6, Nigel Inkster, told The Times: ‘Al-Qaeda have been rebuilding, quietly and waiting out Islamic State, waiting to see Islamic State come under the pressure it has come under.’
On Monday, a leading figure in al-Qaeda who became a prominent member of its Syrian Nusra Front offshoot was killed in a drone attack.
They said Sheikh Abu al Faraj al Masri, who spent years in prison in his native Egypt on charges of plotting with fundamentalist Islamist groups and later left for Afghanistan, died when the vehicle in which he was travelling was hit in rebel-held Idlib in Syria's northwest.
'May God accept him as a martyr who was killed in a Crusader raid,' said a jihadist named Abu Mohammad al Shami.
The U.S. Defense Department said in a statement that Masri was the target of a U.S. air strike near Idlib on Monday. 'We are still assessing the results of the strike,' it said.
Since the U.S.-led coalition launched operations in Syria, primarily against Islamic State militants, air strikes have also targeted Nusra Front figures, killing scores.
Osama bin Laden’s (right) son Hamza (left) is now thought to be 25 years old and living in Pakistan but he has not been pictured since he was young
It was believed at first that Hamza had been killed in the raid that killed his father at this compound, with his death announced by the White House
In Hamza bin Laden’s latest audio message, which was released by al-Qaeda's propaganda arm Al Sabaha in August, he rails against the Saudi government and calls them 'great criminal thieves' and 'agents of the Americans'.
Hamza has followed his father's footsteps in attacking his home nation of Saudi Arabia and condemns its relationship with the US.
He also blames them for betraying Yemen by attacking al-Qaeda jihadis fighting against the Shia Houthis in the civil war.
Saudi Arabia has bombed rebel groups fighting in the country, which is largely a conflict between Sunni-Shia factions.
‘Our brothers there presented great sacrifices and gave enormous efforts in serving the Muslim public in Mukalla, as witnessed by the near and far,' Hamza says, according to a translation produced by jihadi tracker SITE Intelligence.
'But [the House of Saud] did not leave them alone, neither in fighting the Houthis, nor in establishing the sharia of Allah among the Muslims and serving their needs.
'[The Saudis] attacked them, thus protecting the transgressing Houthis from the strikes of the mujahideen.'
Hamza has followed his father's footsteps in attacking his home nation of Saudi Arabia and condemns its relationship with the US
Osama was killed in Abbottabad, Pakistan on May 2, 2011, by US Navy SEAL Team Six
The audio message was distributed on social media channels and is more than 26 minutes long.
Unlike slickly produced ISIS propaganda videos, the recording is screeds of Arabic text interspersed with photographs.
This is not the first time that Hamza calls for terrorist attacks. Previously, he has incited attacks on on London, Washington, Paris and Tel Aviv in an audio message released by al-Qaeda.
Hamza is thought to have been groomed by his 9/11 mastermind father.
He can be heard on previous audios urging lone wolf attacks against the West.
Rita Katz, director of SITE Intelligence Group, tweeted: 'Hamza Bin Laden, son of Usamah bin Laden, gives strategies in continuing global jihad in audio message.
'Hamza Bin Laden lived the life of jihad with his father throughout AQ’s (al-Qaeda) creation in Afghanistan.
'With Hamza, AQ hopes to renew the popularity of AQ by reviving the brand of "AQ = Bin Laden".
'AQ leadership wants Hamza as a future leader: someone loved & inspirational, without a negative reputation or participation in infighting.
'Hamza Bin Laden calls to move the war from Kabul, Gaza & Baghdad, to Washington, London, Paris & Tel-Aviv. Urges: "This is your duty”.
'Hamza Bin Laden urged lone wolf attacks in the US and the West; targeting of Jewish American interests globally.'
Osama was killed in Abbottabad, Pakistan on May 2, 2011, by US Navy SEAL Team Six.
Following his death, dozens of letters written by him to his family and senior members of al-Qaeda were released.
Senior intelligence officials claim some revealed he had been grooming his son to take over the terror group.