Why does it happen?

If you've never got the phone wet, how can you possibly have moisture damage in your mobile phone? The answer is condensation.

Here's a selection of explanations from manufacturers, sellers and repairers:

Telecom: "Some of the more common water damage we see is as a result of customers accidentally getting water in their device by answering a call with wet hands for example or taking their phone running and having it close to wet skin."

Vodafone: "Anything from being left in a bag with other liquids (for example, hand cream, drink, etc) to condensation from cold products if the two items are in close proximity. People tend to leave them in jacket or trouser pockets - unless you're wearing waterproof clothing, that can cause problems if you're out in the rain."

Telegistics: "The handset does not necessarily have to be splashed, soaked or immersed in liquid to be damaged ... Keep your handset away from anywhere wet or moist (kitchen windows, steamy bathrooms, sweaty pockets, wet hands, rainy days, near drinks/drink spills, bar/pub tops, tables are just some common areas)."

Nokia: "If the customer is living in a location where the environment is quite damp or the humidity is quite high, that can cause moisture to get into the internal components of the phone."

The user guide for one Nokia phone says to not only keep the phone dry, but to avoid storing the phone in hot and cold areas: "When the device returns to its normal temperature, moisture can form inside the device and damage electronic circuit boards."

Using this rationale, it seems impossible for a mobile phone to survive more than a few weeks in the humid equatorial regions of the earth - much less in areas that have extreme temperature changes (like Scandinavia, which just happens to produce many of the world's mobile phones).

Telecom appears not to be taking its own advice - stills are from the "Clever Toys" TV advertising campaign in 2007.