Microsoft is preparing to "end sales" of its Lumia smartphones by the end of the year, according to an anonymous internal source.

And in a decision that will surprise almost nobody, Microsoft is believed to be planning to replace its underperforming Lumia range with a new Surface Phone.

The anonymous tipster's predictions have seemingly been borne out recently, both by the fact that just four Lumia models are left on the market, with no more forthcoming, and by reports that many retailers have been offering discounts and removing the phones from in-store prominence. Microsoft has even removed the link to buy Lumias from its US website, and dialled back their presence in other regions.

According to WinBeta, which first broke the news, the source says that the Lumia brand will be totally removed from sale by the end of the year, rather than just having production ceased. The speculation is that this will make space for the rumoured Surface Phone, a notion corroborated by a pair of now-deleted tweets sent one of Microsoft's engineering directors, Laura Butler, who wrote "Surface iPhone. ;-)" on September 6, and "Surface Phone not NOT confirmed. :-)" on September 7, in reply to questions.

The firm is thought to be holding an event in October to announce a Surface all-in-one, which is when the phone could be revealed as well, or it might be held back for an event in 2017.

While Microsoft seems to be closing the book on its experiment with Nokia and laying off thousands of employees it acquired during its ill-starred takeover of the Finnish phone company, it would still come as something of a surprise if it stepped out of the smartphone game for good, especially as it does still seem to be enthusiastic with its other Surface products.