Metropolitan police commissioner Hogan-Howe said the police have stopped “four or five” terror attacks already this year, in comparison to one per year in recent years. He estimated that 500 people have left the UK to fight for extremist groups in Iraq and Syria. Khalid Mahmood, a Muslim MP from Birmingham, said 2,000 is a better estimate, and that the growing number of British jihadists is “a huge, huge problem.” Mahmood also warned that the government has not effectively stopped the flow of jihadists in and out of the country. The Muslim Council of Britain said authorities should arresting more would-be jihadists as they try to leave the UK. Police are starting a public campaign to raise counterterrorism awareness this week.