It most definitely is safe for international students to study in the UK. Schools, colleges and university campuses in the UK are exceptionally safe places. Schools are very secure, many have electronic safety gates, security guards and other measures to ensure that pupils are safe at all times. As well as taking health and safety precautions, staff have a duty under the common law to take care of pupils in the same way that a prudent parent would do so. Pupils are monitored by school staff, all of whom have been DBS checked (police checked) and who have taken various child safeguarding courses. It would be very difficult for a terrorist to get into a school in the UK.