Yeah, sadly its a ground up build, so OS is needed.

very interested in this build, if I did upgrade to the 1070 gtx, it would still run well with the parts listed here?

Here is what that price will get you:

PCPartPicker part list: https://uk.pcpartpicker.com/list/W8bBWX
Price breakdown by merchant: https://uk.pcpartpicker.com/list/W8bBWX/by_merchant/

CPU: Intel Core i5-7500 3.4GHz Quad-Core Processor  (£187.99 @ Aria PC)
Motherboard: Asus PRIME B250-PRO ATX LGA1151 Motherboard  (£84.01 @ More Computers)
Memory: Kingston FURY 8GB (2 x 4GB) DDR4-2400 Memory  (£63.98 @ Ebuyer)
Storage: Western Digital Black 500GB 2.5" 7200RPM Internal Hard Drive  (£50.25 @ Amazon UK)
Video Card: Asus GeForce GTX 1060 6GB 6GB Dual Video Card  (£239.94 @ Aria PC)
Case: Thermaltake Versa H23  ATX Mid Tower Case  (£26.48 @ Aria PC)
Power Supply: EVGA 500W 80+ Certified ATX Power Supply  (£39.00 @ Aria PC)
Optical Drive: LG GH24NSD1 DVD/CD Writer  (£13.95 @ Amazon UK)
Total: £705.60
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-03-22 20:59 GMT+0000

And it will certainly perform better than a ps4 pro in most games. We don't really know Scorpio so idk about that. What I do recommend however is to spend $150 more on a 1070 instead or wait a couple of months until AMD's Ryzen 5 CPUs come out which may lower the cpu cost more. Also add like $20 more for Windows 10 from Kinguin.

Lol, no doubt.

very interested in this build, if I did upgrade to the 1070 gtx, it would still run well with the parts listed here?

Yeaa! After the 1070, the total power requirement according to PCPartPicker is about 310sh Watts so a 500 Watt Powersupply is still more than enough. And the bottlenecks will be minimal. If you do decide to get an SSD, you can choose a western digital Blue hard drive instead of their black series since the Blue ones are cheaper but not as fast which won't really matter much since an SSD is faster than both.

But on a budget build, SSD's don't benefit gaming all that much in most cases apart from faster loading times hence why I didn't bother to include it since that money could be going else where like more ram for example. Yes, the OS would be more snappy and the PC in general just feels faster but getting an i5 or 1070 or 16gb of ram would benefit you more in terms of gaming than an ssd will. But if you get an i5 + 1070 + 16gb of ram and still have enough money to get an ssd, go for it but it is certainly going well above the inital price range.

As some have said, there are ways to get cheap keys for one, so it shouldn't be a problem if you're ok using ebay or similar alternatives. If not, it will take a noticeable chunk of your budget.

That's a well rounded build if you don't plan to overclock (for that you need a "K" CPU from Intel and a Z motherboard), although I would advise you to get 16GB of RAM, not 8. I know it sounds like a lot, but there are games like Battlefield that already run better with 16GB than with 8.

The 480/1060 cards are more than enough to play current games at Full HD (by the way, I assume you already have a monitor/TV to play). The 1070 is an excellent purchase, tho (I should know, as I got one!).

Lastly, but only if you can, try to get an SSD. Even if it's only 64 or 120GB (enough for the OS and other system programs) with a regular HDD for the games, you'll notice the PC to feel faster and snappier.

It's true but not many people know about it still. They are legal Windows 10 keys from scrapped PCs - you download and install Windows 10 from the official Microsoft website then buy the 5 usd key on ebay and activate your Windows 10. So the argument in favor of consoles that you need 100 usd OS for your PC does not hold anymore.