First it was Sony laptop batteries bursting into flames, then came last week’s set-top box inferno. Now Apple’s diminutive iPod nano has been catching fire.

According to an official from Japan’s Ministry of Economy, Trade and Industry a safety investigation has been launched after an iPod nano started sparking while being charged.

As you’d expect from tiny sparks issuing from a tiny MP3 player, no one was hurt in the January 8 incident in the Kanagawa district near Tokyo.

But imagine the consequences if the nano owner had decided to charge his iPod near a bale of hay or pile of kindling or even at a petrol station.

Apple is investigating the cause of the sparks and trying to establish if there have been any other similar cases.

On its website, Apple advises: "Charging your iPod, iPod nano or iPod shuffle while in certain carrying cases may generate excess heat, which can affect battery capacity. If you notice your iPod gets hot when you charge it, take it out of its case first."