As has been pointed out, some US companies have had this policy for many years, and not a few of them are in the IT services area operating in the UK. One company with which I dealt with was such that an air of paranoia gripped all there staff. Despite being from a really big name company, many were dropped into roles they were ill-equipped and trained for and they lived in fear of being part of the regular cull. Of course they rather knew the cultures of the organisations that they were joining, but this is not spreading to other UK companies that didn't operate this way before. One CEO declared several months ago that he expected 2,500 people to be managed out of his company within the year using "performance management" (something that might come back to haunt him in the future).
This stuff can be incredibly corrosive. Enron, to a large part, be became the massively fraudulent organisation it was, not just because of crooks at the top, but due to the fire the bottom performers methodology. Essentially if targets were not met, you were on the conveyer belt to the back door. What that generated was an internal industry for fraudulent financial and sales figures. Run a company on very short term fire the bottom X% annually (and in some organisations this can happen within just 4 or 5 months), and just watch teamwork replaced by paranoia and a mad scramble for survival.
Of course if the various HR organisation that are promoting this (at the behest of accountants) get found out when this "quota" approach is exposed and hits the employment tribunals, then it could get expensive. But then some companies might feel that's still a cheaper price to lose a few of those cases than pay redundancy. Bad financial times will encourage more of this behaviour, so expect a backlog in UK employment tribunals in a few months' time.