[arethuza]

parliament.uk - not really a TLD though

http://www.parliament.uk/

All MP email addresses appear to be <name>@parliament.uk

[zokier]

That's squarely a second level domain, not top-level one.

[mattmanser]

Until last year all uk addresses were in the format of domainname.x.uk, where x mimicked the US tlds, .org.uk, .gov.uk, .co.uk (instead of .com.uk), etc.