Nearly one-in-ten customers have switched banks or retailers because of unhappiness over the way they have handled their identity or privacy, according to the bi-annual Unisys Security Index.

According to the Index, 85 percent of the population are now worried about bank card fraud and identity theft, with 75 percent of British people saying they will not shop or bank with people they cannot trust to safeguard their personal information.

But the Index also showed UK customers take a selective approach to online safety. While a majority limit access to personal information on social media sites, 39 percent admit to rarely considering privacy protection when shopping or banking online.

The Unisys Security Index tracks consumer security concerns every six months. While the latest Index finds overall security concerns are down compared with April 2010 (from 127 down to 112 out of 300), Unisys says UK consumers remain acutely concerned about issues like bank card fraud and identity theft.

According to the study, 85 percent of Brits are "worried" about other people obtaining their credit or debit cards (of which 56 percent are "seriously concerned"). A similar percentage is worried about identity theft (of which 55 percent are seriously concerned).  UK consumers are more concerned about ID theft and bank card fraud than meeting their financial commitments, of which only 22 percent are seriously concerned.

Unisys says these fears are reflected in the UK government's National Security Strategy, which listed attacks in cyber space as a top threat facing the UK. And the National Fraud Authority has found that nearly two million people fall victim to identity fraud a year.

Benjamin Williamson, senior economist at the Centre for Economics and Business Research, said customers jumping ship in response to perceived poor security was "bad news" for banks and retailers. "Retailers and the financial services industry have traditionally relied on customer loyalty to maintain a steady and healthy customer base, but the economic meltdown has effectively unseated the status quo."

Williamson said: "In our own research we’ve seen that consumers are challenging their suppliers over IT and customer service. But the jury’s out as to whether they’re addressing these challenges, and if not, what the outcome will be.”

The Unisys Security Index surveys more than 10,500 people in 11 countries: Australia, Belgium, Brazil, Germany, Hong Kong, Italy, the Netherlands, New Zealand, Spain, the UK, and the US. In the UK, more than 970 UK citizens responded to the latest survey.

The study measures consumer perceptions on a scale of zero to 300, with 300 representing the highest level of perceived concern. Lieberman Research Group conducted the survey in Brazil, Europe and the US.