I assume that the EU has a standardized set of regulations. But just speaking anecdotally, I know of at least three people who were able to take things through security in Madrid, flew to London to transfer (which meant that they had to go through security again) and were unable to carry on things that had made it through Madrid security. One set of hiking poles, one was a large umbrella, and the other was some paste in a jar that was deemed too much of a liquid by London security.
I have always checked my poles for the return trip to the US just to avoid potential problems. And if they don't make it, it's not a problem since I'll be finished walking for a while.
Buen camino, Laurie