there's two distinct "waves" - the first wave, post WW2 won't have passed the language on, but the second wave is much more recent (2004-now) and, of course, they'll all speak Polish.
Its not really that clear cut though. Ive met old Polish men who married English girls in the 40s and who now hardly remember any Polish themselves. But,on the other hand I did surprise the heck out of one of my old high school teachers by chatting in (limited ;) ) Polish with him a couple of years ago, he was second generation, his dad came during the war and passed the lingo down,as did my teacher to his kids.....
Many of these I assume left from Poland not to long ago. Surely Percentage wise Britain has more Polish speakers than US?
purely % wise thats probably the case, but,has been for a while. Its an old joke that my towns Yellow Pages had huge M, O and Z sections ( The Mc'scotties,the O paddies and all the Z...ski's :) )
Dessi, thats the way things work in your country with its long held obsession with making damn sure people knew their place ,people are not simply allowed to be American,they have to be "something-American" where as here,until only a few years ago,once you came here and decided to live here you were British,no matter how funny your accent or unpronounceable your last name :) No one is forced to forget where Granddad may have come from just because people dont feel the need to call themselves "something -British" :)