I will land on Heathrow airport on a Sunday morning (October 23rd, 8:30 am) and take the national express bus directly to Gatwick (bus leaves at 10:05 am). I will have five hours between landing and flying again from the next airport (Next flight leaves at 1:10 pm). I also have no check-in luggage and will do online check-in for all flights. I thought all was good until a friend from London told me it took him twice over 3 hours with that bus due to traffic jam as the bus drives in one of the main highways and suggested that going from Heathrow to city center with the train/subway and from there head to Gatwick would guarantee that I will make it in time. So How is the traffic jam on a Sunday morning in the highway connecting both airports?
The roads are the M25 and M23 and early on a Sunday are quite likely to be deserted. There are no significant road works on either at present. Your transit time should be about 45 minutes. With heavy traffic it can take just over an hour. The distance is 38 miles, according to Google Maps.
At the moment The AA is showing 57 minutes as there is some delay from an earlier accident and a section of the M25 (the London Orbital) is slow due to lane closure. It shows the distance as 44 miles and 49 minutes for the standard journey time. Note that sections of the M25 are limited to 50 mph during busy periods but, as mentioned, that should not include Sunday mornings.
National Express shows a single ticket is £20 and both 45 mins – fastest journey time and Our direct coach transfer takes just 1 hour 15 minutes† - that's 15 minutes faster than the train, and doesn't involve any changes. Where the associated note is Travel time indicative of fastest travel between Heathrow terminals 1,2 & 3 and Gatwick South. Travel times may differ depending on time of travel and at peak travel times.
The route is:
and some of the apparent time discrepancies are due to pickups and drop offs and a little bit of travel between stops.
A snip from a timetable is:
At present there are (temporary) roadworks on the M25 and four lanes are down to one (eg see this camera) but nevertheless Google Maps is indicating 37 minutes by car. Coach may take about 10 minutes longer than car, between T5 and N.