The days of the iPhone 3GS look to be numbered with reports suggesting that supplies of the device are running low ahead of a planned discontinuation of the product in the autumn.

A number of suppliers and mobile networks around the world are reportedly seeing dwindling numbers of the iPhone 3GS, ahead of the rumoured launch of a next-generation iPhone in September.

A source at an Orange UK store told 9to5Mac that employees have been advised that the iPhone 3GS is no longer available. You can still order an iPhone 3GS through the Orange UK website though.

Indeed, O2 , Vodafone, Three and T-Mobile all still have the iPhone 3GS listed on their sites. You can also still buy an iPhone 3GS through the Apple UK Store SIM-free for £428.

The next-generation iPhone is expected to launch in September and though some reports suggested that Apple might keep the iPhone 3GS as its low-cost option when the iPhone 5 launched, evidence seems to suggest it will be scrapped.

It was reported last month that Apple would launch not one but two new iPhones in September, one of which would be a low-cost model, which if true would put the final nail in the iPhone 3GS' coffin. However, 9to5Mac speculates whether the reduced supply could hint at Apple giving the 3GS a makeover, upgrading the screen or processor.