Nearly one in 10 people believe they have fallen victim to identity fraud, a survey has revealed.

The study found people aged under 30 are the most prone to falling victim because they are the poorest at protecting personal details, the survey commissioned by electricity company npower said.

The study revealed that 22% of people are unaware that a utility bill can be used to steal someone else's identity. Moreover, more than two-thirds of those under 30 have at some time given friends or family secret details such as PINs, bank account details and on-line bank passwords.

In contrast, 40% of people aged 30 to 50 and 33% of over 50s had disclosed details. The majority of the under 30s (81%) had no idea what their credit rating was and 59% did not know how to find out.

Zoe Coombs, from npower, said: "The under 30s are at higher risk of becoming victims or of putting others at risk as they are more likely to be nomadic, living in rented properties, moving out of university halls and so on."

"It's vital that they are educated to dispose of documents responsibly and ensure that they do the same with other people's mail."

Moving house was pinpointed as a particularly dangerous time, as far as falling victim to identity theft is concerned.

The survey found that many people's energy bills and bank statements went astray when they moved. "August is the most popular time of year for moving property, therefore the risk of ID theft is increased," said Zoe Coombs.

Npower’s figures, obtained by YouGov who questioned 2,200 adults, suggest more than six million people have been affected by ID fraud. This is far higher than official figures from UK's fraud prevention service, CIFAS, who say reported cases of identity theft has risen from 20,000 in 1999 to 137,000 in 2005.

However, Professor Martin Gill, identity theft specialist and professor of criminology at Leicester University, said the number of ID thefts was far higher than the number reported.