For peace of mind, allow at least 2 hours before short-haul flights when departing for Gatwick, and more for long-haul

https://caidenadlp413.huicopper.com/best-way-to-gatwick-airport-with-luggage-or-kids-1

For peace of mind, allow at least 2 hours before short-haul flights when departing for Gatwick, and more for long-haul. Add buffers for rush hour or weekend engineering.