Isis “aims to attack the UK next,” an intelligence report has warned.

The unnamed official, speaking to CNN, claimed following the Paris attacks counter-terrorism authorities believe Isis will attempt to hit Britain.

They claimed British Isis fighters have been told to return home and carry out an attack by senior leaders of the extremist organisation, also known as the Islamic State or Daesh.

Details around the alleged threat are unclear, but the official claimed authorities’ concerns were heightened by MPs decision on Wednesday night to extend air strikes over Syria.

The controversial vote was won by 174 votes, with Britain launching the first round of strikes against Isis within hours of securing the Commons approval.

Tornado jets struck six targets in the Omar oil fields, around 35 miles east of Raqqa – Isis’ self-titled capital. Defence Sectary Michael Fallon said the first strike, aiming to dent the extremists ability to sell oil, was “extremely important”.

British jets prepare for air strikes in Syria Show all 10 1 /10 British jets prepare for air strikes in Syria British jets prepare for air strikes in Syria A Tornado jet takes off from RAF Lossiemouth in Scotland, as RAF Tornado jets carried out the first British bombing runs over Syria British jets prepare for air strikes in Syria Pilots and ground crew prepare combat aircraft Panavia Tornados at RAF Marham at RAF Marham, UK Getty British jets prepare for air strikes in Syria A Eurofighter Typhoon jet takes off from RAF Lossiemouth in Scotland, as RAF Tornado jets carried out the first British bombing runs over Syria British jets prepare for air strikes in Syria A RAF Tornado arrives at RAF Akrotiri to begin operations in Akrotiri British jets prepare for air strikes in Syria A Tornado jet ahead of taking off from RAF Lossiemouth in Scotland, as RAF Tornado jets carried out the first British bombing runs over Syria, the Ministry of Defence has confirmed. The air strikes were carried out within hours of a vote by MPs in the Commons to back extending operations against Isis from neighbouring Iraq British jets prepare for air strikes in Syria Personnel work on a British Tornado after it returned from a mission at RAF Akrotiri in southern Cyprus British jets prepare for air strikes in Syria Two RAF Tornado GR4's, both with remaining weapons ordnance, approach RAF Akrotiri in Cyprus, as they return to the base after carrying out some of the first British bombing runs over Syria British jets prepare for air strikes in Syria A RAF Tornado takes off from RAF Akrotiri, on the Mediterranean island nation of Cyprus British jets prepare for air strikes in Syria A Tornado jet leaving RAF Lossiemouth in Scotland British jets prepare for air strikes in Syria AKA RAF Tornado arrives at RAF Akrotiri to begin operations in Akrotiri, Cyprus. The RAF has sent two further Tornado aircraft and six Typhoons to bolster aircraft now flying sorties to both Iraq and Syria

Meanwhile, authorities have also sought to limit fears of civilian casualties.

“In the hundreds of air strikes that the RAF has carried out in Iraq, we have had absolutely no civilian casualties reported,” Group Captain Richard Davies, Tornado pilot and station commander at RAF Marham, said in a statement.