BA 371 then UA 26 at Heathrow
Toulouse → London → Denver
Timetable, London time
12:25BA 371 from Toulouse at the gate
11:35UA 26 to Denver leaves the gate
23 h 10 apart on the timetable, overnight
UA 26 leaves 23 h 10 after BA 371 arrives on the timetable: more than half a day, so not a connection we count.