Another day, another white iPhone 4 rumour: The long-awaited device is to launch on international markets this week, perhaps even tomorrow.

Engadget reports that the white iPhone 4 has been spotted on Vodafone UK's inventory and that it will launch this week.

Apparently, one lucky punter has even managed to get their hands on one thanks to a helpful sales assistant at the company, though Vodafone has temporarily halted any more sales until either Tuesday or Wednesday of this week. Officially, Vodafone's site says that it will be offering the white iPhone 4 just as soon as Apple launches it.

9to5Mac reckons that Wednesday 27 April will be the day, for Europe at least. There have been sightings of the white iPhone 4 in the US, according to Apple Insider.

There had been speculation last week that the white iPhone 4 was to launch before the Easter weekend.

Last week pricing and delivery information appeared briefly on network operator Three's site, only to be hastily removed. However, the PhoneItalia website had previously named the launch date as 26 April.

It is thought that number of manufacturing issues have held up the release of the white iPhone 4, which was supposed to launch alongside the black iPhone 4 in July 2010, including paint that peeled under extremes of heat.

Steve Wozniak also speculated that paint was part of the problem back in January, though Woz reckoned it was letting too much light in to the body of the phone, ruining photographs and videos captured by the device's camera.