Home Office says 700 people 'of concern' have travelled to conflict zone Intelligence agencies claim around half of them are now back in Britain Ministers warn of plots targeting public events and the armed forces At least 350 British jihadis are back in the UK after fighting and plotting terror attacks in the ISIS-'braincell' of Syria, the government warned today. Spy agencies and the police are concerned about as many as 700 people from the UK who have travelled to the region since the start of the conflict, and around half have returned to Britain. Ministers today warned that there...