Considering that 1) the revenue base of ARM is predominantly in USD licensing fees, and 2) that the British pound has lost ~20% against he dollar. The ~41% premium is really a 21% premium. No chance a global leader like ARM could have been snatched for a 21% premium a few weeks ago.

Run a list of companies listed in London with predominantly non-GBP revenue base and you have a great list of takeover targets.