BA 961 then UA 4 at Heathrow
Hamburg → London → Houston
Timetable, London time
12:20BA 961 from Hamburg at the gate
12:05UA 4 to Houston leaves the gate
23 h 45 apart on the timetable, overnight
UA 4 leaves 23 h 45 after BA 961 arrives on the timetable: more than half a day, so not a connection we count.