Things go wrong. The problem is, we can never be sure what might happen, when or the exact effects. What we can do is make sure we are as prepared as possible to react to a range of circumstance.
This guide from EJC covers the key aspects of business continuity from a tech point of view. It covers risks, systems, remote access, backups and recovery, staff/client communication, physical equipment and more. A highly useful read.
Disclaimer: I have worked closely with EJC for several years now. I trust their advice implicitly, and while I’m not being paid or compensated to add their advice here, they are a client of mine.