Its *extremely* rare to see anything like that in the UK. Since the introduction of the BS1363 plug/socket system in 1947, an Earth connection to each BS1363 socket has been mandatory and the pre-BS1363 sockets were round pin, so visually distinct, and usually had to be replaced to make a property saleable. Its often a condition of buildings insurance that an electrical inspection has been performed within a certain number of years and any issues found remediated and DIY work now requires inspection so you typically only see the like when a resident since WWII or shortly thereafter who hasn't had significant electrical work done since the '60s dies or is taken into care.
Well, consider yourself lucky then - most of the continent doesn't allow such installations anymore, but unless the building is being renovated/major work is being done, there is usually no obligation to replace the wiring (= enormous expense)
E.g. in Denmark where I lived or here in France it is very common - in my current apartment which is in a fairly recent block of flats (perhaps 15-20 years old max.) I have several outlets that have only two pins (no ground) and are not even recessed - similar to the US-style outlets, only with round holes, so if you aren't careful, you could get shocked while inserting/removing the plug. In Denmark you will commonly find round outlets (like the French or German Schuko style) but with no earthing prong nor contact - only two pins for live and neutral.
Two wire/no ground wiring is still fairly safe for normal indoor installations (unless some retard connected the neutral and grounding pins in the outlet!) where most of the appliances are doubly insulated anyway. The only exceptions are typically large appliances like water heaters, ovens, washing machines, etc. - there it was common to require separate grounding for them.