One in five of us have mislaid a portable device containing phone numbers, contact details or images. That's according to a survey by YouGov, which claims that the 'digital generation' is in danger of losing valuable images and data forever.

Of the 2,035 British adults questioned, 40 per cent admitted to not backing up the photos stored on their digital camera or mobile phone. And while 58 per cent of those who own a portable device said they store up to 500 photos on it, only a handful - 6 per cent - were found to be worried about losing the data.

What's your number again?

That's despite nearly two thirds of those who lost phones saying they had to track down the lost contact details from scratch. Surprisingly, only 44 per cent said this had made them think twice about backing up information in future.

And the age group that has lost the most portable devices containing phone numbers and contact details? At 33 per cent, it's the 25 to 35-years-olds. Not surprisingly, the over 55s, at 8 per cent, were found to have lost the least.

"Data backup and protection is not just a concern for businesses. Today's 'Digital Generation' load an increasing amount of information onto phones, iPods and laptops every day, and with this comes risk," said Mark Stevens of NetApp - which commissioned the survey.

It seems there's also a gender difference in attitudes towards the loss of digital images. Three times as many women said they were very worried about losing their photos than men, according to the survey.