How full proof is your Business Continuity Plan?

Question for your IT manager
Q. In event of a disaster (such as a fire) how quickly can you have us back up and running?
A. If they have considered the above – the answer should be less than 4 hours

The more your business relies on its IT systems, the more you need to consider how unexpected disruptions might affect your business. These disruptions could come in many forms, from fire and floods to theft or malicious attacks on your systems, such as viruses or hacking.
Business continuity planning improves your business’ ability to react to such disruptions. It describes how you will restart your operations in order to meet your business-critical requirements.
The main benefit of business continuity planning is enabling your business to recover quickly from unexpected events that disrupt your IT systems.
A business that can demonstrate an effective business continuity plan has a competitive advantage. For example, if you provide services to customers that are dependent upon your IT systems, like an internet service provider, then evidence of a sound plan can be used to win or retain customers. For instance, if your business is a partner in a supply chain, business continuity planning may well need to be an integral part of your quality assurance.
Your Business Continuity plan should aim to reduce the risks posed by disruption to your business processes. Measures that you need to include:
• A back-up and data recovery strategy, including off-site storage.
• The development of a resilient IT infrastructure with redundancies (spare capacity) in case of failure. For example, mirrored central server computers sited in different locations, each containing the same information, so that if one goes down, the other one is available to ensure continuity of service and alternative storage facilities.
• The elimination of single points of failure, such as a single power supply.