Microsoft's Windows 10 event next month is looking even more crowded after leaked images of a low-cost device dubbed the Lumia 550 surfaced online, Digital Spy reports.

Made from glossy polycarbonate with a metal frame, the handset promises to offer the mobile version of Microsoft's new operating system to those on a budget.

Specs details published by Russian website onetile and verified by wmpoweruser place the smartphone firmly in mid-range territory.

The Lumia 550 is said to include a 1.2GHz Qualcomm Snapdragon 210 quad-core processor with 1GB of RAM, a 4.7-inch AMOLED screen with a 720 x 1280 resolution and 312ppi, and 8GB of storage with microSD expansion.

Camera resolutions were not listed, but the front snapper appears to include a flash to illuminate your selfies.

Expected to cost around £85, the device should serve as a cheap-as-chips alternative to the flagship Lumia 950 and Lumia 950 XL handsets.

Microsoft has been tipped to announce all three phones at its press conference in New York on October 6, alongside a new Surface tablet and Microsoft Band.