I'm going to refer you to my comments in this thread. If your budget is really that low, then your options are limited -
Best stereo upgrade to 1 box home cinema system
For a bit more than that limited amount of money, you can get a pretty fair stereo, but for a Surround Sound system, it is pretty much bottom of the bin.
Another alternative would be high end computer speakers or active Studio Monitors. These are speakers with built in amps.
For both stereo and studio monitors, the first complication is connecting to the TV. The TV must have an Analog (meaning not digital) AUDIO OUT. At bare minimum, the TV must have a Headphone out.
The next problem is the Remote Control. The Remote control of the TV typically will not control the volume of the external speakers. If you have an external free standing amp, then it will have its own remote volume control. With active speakers, which only extremely rarely have remote controls, you can use the headphone out of the TV which will change with the standard volume control of the TV.
While a £200 system is possible, most would feel it is not desirable. There may be some other options, if you could tell us more about your intended purpose and goals. Do you want great sounding movies, or do you just want to improve on the TV's built-in speakers, etc...?
The more we know, the more we can help.
Steve/bluewizard