I was in London for an extended period of medical treatment. I decided to stay in a hostel for reasons of economy . It's fine, as long as your roommates are nice. I have been lucky so far and because of that, I've rebooked for a further 3 weeks. I'll probably extend as long as there have been no problems.
The hostel is hard to find - it's down a side entrance and there is no sign, until you get to the door, where there's a tiny plaque.
Booking has to be done online with a card, presumably to keep.dossers, drunks and junkies out.
The 4 bed dorms, which I stayed in, are rather cramped. There's just space for a bit of luggage and the sink, as well as the bunk beds.
There is no common room or resident's kitchen.
The showers are pretty clean all the time. The lavatories get a bit untidy though as the day wears on.
The local area is great for cheap food, both sit-in meals and from stalls.