The HD TV broadcasts in the UK are 720p/1080i, non HD are 576i. Standard Blu Ray discs and players are 1080p. All current games consoles are 1080p max.
So why do you want 4k/UHD? Upscaling ("blowing up") an image to a higher resolution makes it looks worse. If you have a 1080p TV now and watch an SD TV channel like Motors TV, think how bad that looks and then imagine it 4 TIMES WORSE.
The average human eye cannot see the extra detail a 40-50" 4k TV offers unless you are sitting 3-4' away from it. 5-6' is the minimum distance to get the full benefit of 1080p...
If most of what you watch is 4k and you're buying a massive screen and sitting fairly close to it, I can understand it but in reality, most people physically can't see a difference between 1080p and 4k anyway in their lounge.
If most of what you watch is not 4k, why watch it in lower quality?http://i.i.cbsi.com/cnwk.1d/i/tim/2013/01/27/resolution_chart.jpg