What is this viny plant in the UK?
Alan is right to call this a Cichorium. It is  Cichorium endivia, Endive. It is a tropical plant that is widely cultivated for its edible leaves. However, when it flowers the leaves die, so you don't recognize the plant as Endive. The dying leaves can be seen on the picture below, from the Dutch wikipedia page.



https://nl.m.wikipedia.org/wiki/Andijvie