Officially not released until 14th January, but available from a very small number of retailers early - This is the cheapest I have been able to find from a UK supplier.
Amazon Price: £99.47 (but on pre-order until 14th January)
This is the first Lumia phone that is branded as Microsoft rather than Nokia.
It has camera's on both sides as well as a flash on the back.
I've been using one for about a week and it is great. - Much prefer it to my previous 635 and 520 phones.
I went for the free 5 day delivery, but it arrived next day by Parcelforce.
Here is the full specification
Model Name - 535
Barcode - 6438158703964
Product Type - Smartphone
Product Family - Lumia
Number of Frequency Bands - Quad-band
Mobile Broadband - 3G
Phone Performance (2G)Standby Time (2G): 546 hours (max.)
Phone Performance (3G)Talk Time (3G): 13 hours (max.) Standby Time (3G): 540 hours (max.)
GSM Performance - Talk Time: 660 minutes (max.) ,
Internal Display - 5ins , 960 x 540 Pixels , Colour , IPS
Touchscreen - Yes
Built in Camera - Yes
Built in Radio - Yes
Bluetooth Support - Yes , Version 4.0 ,
GPS Support - Yes
Operating System - Windows Phone 8.1
Case Colour - Black
12/01/15 - Back in stock
13/01/15 - Back in stock
23/01/15 - Price updated from £87.85 to £89.08
06/03/15 - Price reduced - Now £88.31