NEW : Security firm G4S says young people employed for the the Olympic Games will do a good job . Olympic says he is `` extraordinarily impressed with '' security contractor G4S . The deployment means 17,000 troops will be on duty in the United Kingdom during the Games , compared with the 9,500 currently in Afghanistan . An extra 100 troops to be brought in to cover a shortfall in security staff . G4S says it has 100 people at work across about 4,000 venues ; more undergoing training .
NEW : Security firm G4S says young people employed for the the Olympic Games will do a good job . Olympic says he is `` extraordinarily impressed with '' security contractor G4S . An extra 100 troops to be brought in to cover a shortfall in security staff . G4S says it has 100 people at work across about 4,000 venues ; more undergoing training .