If you work late in the evenings or at weekends and work alone you must think about the health, safety and security risks. The major concerns would be if you had an accident or encountered an intruder. There could also be risks for a lone worker having to walk to a transport point.
Porters are on duty on each campus until very late, in some cases beyond midnight.
They can be contacted on internal numbers or pagers. Their numbers are available for each campus in the campus office. You should make sure you know these numbers before working late. It may also be possible for a porter to escort you to your transport.