The iPhone and the Blackberry is as big a threat to personal data security as the home PC, a new government-backed campaign plans to tell people.

According to the UK-based, consumers are storing personal data on smartphones without thinking through the consequences should that device get lost or stolen.

The organisation's research shows that about one in five owners of smartphone devices can expect to lose or have them stolen them at some point, with a growing number packed with data such as social networking logins, informtion about bank sites visited, and a long list of phone numbers.

The organisation also reckons seven out of ten devices will contain email exchanges, more than half social media data, one in five some information relating to online purchases, and one in six might even point to online banking websites.

Having spent the five years since its creation as a spin-off from the now defunct National Hi-Tech Crime Unit (NHTCU) pushing PC security messages, GetSafeOnline now plans to do the same job for mobile devices.

"Users must remember that they are essentially carrying around a tiny laptop with a wealth of personal information that is very attractive to fraudsters," said GetSafeOnline head, Tony Neate. "Don't put too much information on them and there is not a problem."

In Neate's view, people have been lulled by the apparently controlled environment offered by mobile networks into thinking that there is a qualitative difference to the threat compared to PCs.

His organisation's advice is to treat iPhones and Blackberrys as if they were wallets.

Consumers should keep as little on them as possible, password or PIN protect each device, and use encryption wherever possible for data on add-on data cards. Further, consumers should not automatically store any website logins or even keep their own home number in a form criminals might recognise. The weakness of assigning ‘Home' to your own number is that a criminal will try to find out more about the owner by phoning the number.

It is unlikely that consumers will pay much attention to some of this, sound though the advice might be. Users treat phones as intimate personal objects and brook no inconvenience when using them. The best solution to the insecurity of mobile devices is to design them with security in mind and get networks to promote security messages.

Judging by the feature-oriented design of many smartphones, that aspiration is still some way off.