Buying a normal system for 200 pounds is impossible, sorry. If you get a case and a hard disk, you just cant get even a budget one. Especially with your reqquirements. Personally I would just go for:
[PCPartPicker part list](http://uk.pcpartpicker.com/p/kKTHdC) / [Price breakdown by merchant](http://uk.pcpartpicker.com/p/kKTHdC/by_merchant/)
Type|Item|Price
:----|:----|:----
**CPU** | [Intel Core i3-6100 3.7GHz Dual-Core Processor](http://uk.pcpartpicker.com/part/intel-cpu-bx80662i36100) | £95.99 @ Novatech
**Motherboard** | [Asus H110M-A Micro ATX LGA1151 Motherboard](http://uk.pcpartpicker.com/part/asus-motherboard-h110ma) | £53.16 @ Ebuyer
**Memory** | [Kingston HyperX Fury Black 8GB (1 x 8GB) DDR4-2133 Memory](http://uk.pcpartpicker.com/part/kingston-memory-hx421c14fb8) | £38.75 @ More Computers
**Storage** | [Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive](http://uk.pcpartpicker.com/part/western-digital-internal-hard-drive-wd10ezex) | £39.08 @ Amazon UK
**Case** | [Fractal Design Core 1000 USB 3.0 MicroATX Mid Tower Case](http://uk.pcpartpicker.com/part/fractal-design-case-fdcacore1000usb3bl) | £29.64 @ CCL Computers
**Power Supply** | [Corsair CX 430W 80+ Bronze Certified Semi-Modular ATX Power Supply](http://uk.pcpartpicker.com/part/corsair-power-supply-cx430m) | £39.99 @ Amazon UK
| *Prices include shipping, taxes, rebates, and discounts* |
| **Total** | **£296.61**
As it is a great skylake build with DDR4 ram and an awesome integrated GPU, however if you want to cut it even further down the road you will have to go for older parts, which I wouldn't recommend even for a budget build, however if price is that much of a problem, I can build you a lower system.