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

https://zaneyhab896.lowescouponn.com/southend-to-gatwick-airport-routes-costs-and-duration-2

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.