Injury in the workplace: Criminal Injury Compensation Authority

Bob was a staff nurse in the accident and emergency department and was used to dealing with drunk people at weekends. One Friday night, however, he was caring for a patient who had been knocked down by a car. The man's friends were extremely drunk and attempted to interfere with their friend's treatment. Bob asked them to leave, but they refused. He warned them that he would be calling the police but one of them lunged at Bob, who fell backwards against a trolley causing a severe back injury. He was off work for several weeks and was warned that he might never fully recover. How can he obtain compensation?