While everybody I know who rented in London had to deal with mice or bed-bugs (and I don’t fully understand what these are, because before coming to London I never heard of them), at least those on low income, I don’t know of any other place where this is even remotely true.
Unfortunately rent regulations in the UK are designed to protect landlords from tenants, contracts are renewed yearly and you are always at risk of eviction. So maintenance is almost non-existent and if you protest, you will likely end up evicted. After god knows how many years or decades of this state of affairs, the housing stock in London is of a ridiculously low quality, and a local would consider normal to have a mouse in a flat and to have to deal with it (rather than the landlord paying for pest control).
To get what in the continent would be a normal flat, you need to aim at what the locals may call “luxury apartments”. And still, if it wasn’t built after 2010, you’d still have to deal with rotten sash windows, no escalator and other crazy stuff I’ve never seen before.
Mmarq is exaggerating quite a bit. It may be that they are accurately reporting their own experiences, but as a description of typical life in London, take it with a huge pinch of salt.
While everybody I know who rented in London had to deal with mice or bed-bugs (and I don’t fully understand what these are, because before coming to London I never heard of them), at least those on low income, I don’t know of any other place where this is even remotely true.