Best graphics card for under £200 for gaming

please avoid referencing US prices in UK threads when possible, 200 pounds translates to 322 US dollars but that is almost never reflected in the price of the components, the cheapest R9 280x for the UK at this very moment is 220 pounds.

Anyways, if you are willing to stretch your budget that far then by all means go for it, the R9 280x is a strong card, if not you have a couple of options:

stretch your budget by 3 pounds and you can get:
PCPartPicker part list

Video Card: XFX Radeon HD 7970 3GB Video Card (£203.75 @ Scan.co.uk)
Total: £203.75

the r9 280x is basically this card but a bit newer and a bit changed, same basic architecture though, and is still a very strong card.

If you cannot stretch your budget then I would go for:
PCPartPicker part list

Video Card: MSI Radeon HD 7950 3GB Video Card (£174.95 @ Scan.co.uk)
Total: £174.95

an HD 7950, which by all rights a strong card, and it can be overclocked to match 7970 performance anyway (at the cost of heat of course)

Or:
PCPartPicker part list

Video Card: Gigabyte GeForce GTX 760 2GB Video Card (£192.34 @ Ebuyer)
Total: £192.34

an Nvidia GTX 760, which is also a strong card, both of these cards trade blows with one another so it's up to preference and software.