In the unpredictable world of IT and the internet, spells of downtime are an inevitability; an unavoidable problem.

But this doesn't mean they should be accepted and ignored. The consequences of downtime can be grave for smaller companies and brands of all sizes risk losing customers forever if their services are inaccessible.

With this in mind, we asked Paul Burns, national technical director of IT support firm TSG, about the true impact of downtime and what businesses can do to mitigate the effects.

TechRadar Pro: What are the main causes of unscheduled downtime?

Paul Burns: Unfortunately, there's no single cause, which makes preventing downtime more of a challenge. Aging equipment and poor IT security are certainly likely to be a major factor but for those who rely on cloud-based services connectivity is crucial.

It's critical to keep systems fully updated but it's also worth pointing out that as much as 50% of server downtime is caused by badly deployed patches.

TRP: The average European company suffers at least 14 hours of IT downtime per year. What could two days of unscheduled downtime do to a business?

PB: The impact will depend on the type of operation but no business wants their people sitting around unproductive. Some could effectively lose a couple of days of revenue that they'll never recover, or more as they catch up with any backlog that's caused by the disruption.

For those who promise next day delivery or rapid response services the impact goes well beyond the immediate financial loss to result in dissatisfied customers who might not buy again in the future.

TRP: In August 2013, Google went down for five minutes causing a 40% drop in global traffic. How could search engine downtime like this affect online retailers?

PB: Many businesses now rely on search engines to generate traffic to their websites so Google going offline will inevitably have resulted in lost sales, and with online sales accounting for 13% of the UK retail market the total value is likely to have been considerable.

This also emphasises the need to consider redundancy, for example if you rely on internet sales always ensure you have high rankings on other search engines like Bing and Yahoo.

TRP: If one part of your business experiences downtime, how does this affect the rest of the company's systems?

PB: This is an area that is often overlooked as the complex domino effect of a simple system outage is rarely explored. Simple IT failures like database corruption could have fairly dramatic consequences, for example, preventing new orders being taken or deliveries being completed.

The importance of considering all likely outages and having backup processes is key. The best designed systems in the world have outages, so you have to plan for them.

TRP: How do you think unexpected downtime affects a brand's reputation?

PB: Damage to reputation can be difficult to quantify but in many cases it's likely to be far greater than the immediate financial loss.

Almost all businesses set a level of expectation with their customers in terms of the level of service they'll deliver, so if those customers can't get in touch or deliveries are missed, they're likely to look elsewhere. Or worse still, express their dissatisfaction through social media channels

TRP: Do you think many businesses understand the amount of damage (financial and otherwise) that downtime can cause?

PB: I suspect most businesses probably haven't done the calculation to work out the impact and would probably be surprised if they did. One of our customers with a large number of fee earners, all reliant on a live system, recently made a significant investment after evaluating the risks and potential cost to the business.

The result is that we've implemented a high availability solution, full replication, immediate failover and two leased lines sourced through separate suppliers.

TRP: What are the longer-term effects of downtime?

PB: There are horror stories and scaremongering suggesting a high percentage of those that experience downtime or data loss go out of business within a couple of years of the incident.

One thing is for certain, a major outage will take months if not years to fully recover from, and effective disaster recovery and business continuity planning is key to reducing the impact.

TRP: What should businesses do to protect themselves from unscheduled downtime?

PB: Businesses need to address three key areas: maintenance of their systems, IT security and connectivity.

With more than 200,000 pieces of new malicious code generated every single day, a UTM or unified threat management device is likely to provide the most comprehensive level of protection against threats that can originate from a wide variety of sources.

In terms of connectivity, it's important that businesses understand the difference between traditional adsl broadband and leased lines.

Leased lines will come with a service level agreement or SLA but it's worth considering that there's a significant difference between 99%, 99.9%, 99.99% and 99.999% uptime; e.g. 2 nines equates to 3.65 days of downtime per year whereas 5 nines equates to only 5 minutes per year.

Businesses should undertake a full impact analysis on all systems and processes, so the business can implement solutions that meet their Recovery Point Objective (RPO) and Recovery Time Objective (RTO), if the worst should happen.

Clearly many SME businesses today still do not even have an effective disaster recovery (DR) plan and this should be the cornerstone of any mitigation planning.