More than two in five (43 percent) firms are reliant on external web professionals to help create and maintain their websites, says Fasthosts.
Research by the web hosting company revealed that 56 percent of these companies said if their web expert was unreachable they would be unable to implement changes to their website.
Two thirds of companies don't have the contact details or passwords for the provider that hosts their website, while 70 percent admitted not all of their domain names are registered in the name of the business owner.
Furthermore, 70 percent of firms don't have a back-up copy of their website.
A quarter of the companies that use external web firms admitted that problems experienced by the web designer, such as staff shortages or technical issues, had lead to their website being offline, while 17 percent said this down time cost around £1,000 in lost sales and lost staff time.
"For many firms, using external web professionals is a very sensible and rewarding option. However, it is vital that all businesses take simple measures to retain some basic control of their website and protect their investments," said Steve Holford, marketing director at Fasthosts.
"Should arrangements suddenly change, business owners should be equipped to make changes to their online identity and maintain contact with their online audience. The web designers we work with always recommend that clients at least keep a back-up copy of their website design".
Holford also said too many small companies are failing to ensure that their valuable domains and their web hosting are registered in their names and are accessible to them.
"As external parties can come and go, it is vital that businesses protect themselves from potential disruption, losses and reputation damage that an off-line or out-of-date website can cause".
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