Doesn't make the education system of the UK sound very good if they can't produced programmers or engineers in the numbers needed...
Well, yeah. That's part of the problem (dumbing down), though world class education is available if you happen to live near the good schools and get into the best universities.
A major problem is that kids don't choose those key subjects at university (you can't force them!). The other part is that growth in those areas is outstripping supply.
It actually suits the UK (or any country) to import skills that another country has paid to train. Polish graduates are generally good, if a little limited in horizons and lacking some flexibility. Very good English language teaching helps a lot.
If an ambitious, intelligent Pole comes to the UK on a Marie Curie Fellowshop for a few years, and gets into the top 20 universities (UK has about 180, but the top 10-20 are world leaders), they generally have a career for life. They can go to any other EU country, or back to Poland, and their UK experience is highly valued and the immediately go to the top of the pile for Polish grants and positions.