Whut, poshtel?! No, it hasn't anything to do with Posh Spice but it comes from posh + hostel. So basically it's a beautiful hostel (not dirty, not old fashioned, but nice and clean) for the budget price of a hostel. In London there are two really nice poshtels I definitely want to try out:
Generator 37 Tavistock Place WC1H 9SE London
Only a 10-minute walk from St. Pancras!
They have private rooms (doubles from £24.50 | triples & quads from £16.50) and (female) dorms from £12. All rooms have free linen and storage.
PS: Generator owns hostels in all big cities (think Venice, Berlin, Barcelona, Copenhagen, etc.)
Safestay 144-152 Walworth Road London SE17 1JL
Safestay is located in South London near Elephant & Castle, which is less central but still a good location.
They are also less cheaper than Generator. They have private rooms from £58 (which is quite expensive in my opinion) and dorms from £18. All rooms have free continental breakfast, bed linen and lockers under each bed. The private rooms also have a TV and free towels.
[All prices are per person and per night.]