Khalid Mahmood, MP for the Birmingham constituency, claimed that official figures on the numbers of British terrorists is grossly underestimating the size of the problem.
UK security officials believe in the region of 500 men have travelled to Iraq and Syria, but Mr Mahmood claims this figure is widely inaccurate.
He said: 'The authorities say there are 500 British fighting in Syria and Iraq but the likely figure is at least three to four times that. I think 2,000 is a better estimate. My experience in Birmingham is it is a huge, huge problem.'