London: As many as 2,000 Britons have travelled to Syria to fight alongside the Islamic State (IS), four times more than the official estimates, a Muslim British parliamentarian has claimed.
Khalid Mahmood, the Labour MP for Birmingham Perry Barr, a constituency with a significant number of Muslims, has suggested this was a fourfold underestimation of the number of British jihadists fighting in the region.
"The authorities say there are 500 British jihadists but the likely figure is at least three to four times that," he told 'The Telegraph'.
"I think 2,000 is a better estimate. My experience in Birmingham is it is a huge, huge problem," he added.
The UK government has refused to say how many Britons had been arrested at UK borders in connection with terrorism in Syria, adding to concern the figure is very small and that the borders are worryingly porous.
Home Secretary Theresa May in an attempt to get to grips with the terrorist threat, will outline measures in a counter-terrorism and security bill requiring Internet companies to keep data allowing police to identify terrorists who plot attacks online.
Mahmood, England's first Muslim MP and a former member of the Commons home affairs committee, said: "The Government does not have significant people at border control. The fact is these jihadists are coming in and going out without almost ever being arrested."
"We have had hardly any arrests. We have had people coming back in after six months in Syria and they are not being picked up."
The official figure of 500 jihadists was released by the authorities six months ago and has not been revised.
IS has since stepped up its recruitment drive by issuing gruesome videos of the murder of Western hostages.