UA 929 then BA 850 at Heathrow
Chicago → London → Warsaw
Timetable, London time
05:55UA 929 from Chicago at the gate
18:15BA 850 to Warsaw leaves the gate
12 h 20 apart on the timetable
BA 850 leaves 12 h 20 after UA 929 arrives on the timetable: more than half a day, so not a connection we count.