Yeah, it'll play the normal UK game cartridges no bother. Compatibility issues with some other formats are usually only due to differences in TV screen resolutions or something along those lines in different areas of the world, but obviously with a handheld you don't get that problem as it has its own screen, lol.

Hence I bought my PSP from Japan when they first came out, but always hang on 'til they're out over here with the consoles.