Travel from London Hotel to Heathrow for early a.m. flight

Since there are 2 of you consider booking a car. We just finished that tour and had an equally early flight at Gatwick which is further. A car was £55. The concierge urged us to book it online as the rate he could get us was over £100. Saved dragging bags to the tube at 5AM. And yes, you should be there 3 hours ahead of time.

The Piccadilly Line now runs all night to Heathrow on a Friday night/Saturday morning. I would just go to Green Park station at 0430 - much cheaper than a cab and there are elevators at both Green Park and Heathrow now.

The tube is not any faster at different times. it takes the same time as it still stops at the same stops.
Where are you flying to? What does your airline say is the recommended time to be at check-in?
This can be 1-2 hours for European flights, 3-4 hours for intercontinental.

09:00 departure, -2 hours = 07:00 at airport, = 06:00 at tube station. Not sure Heathrow Express would be any quicker.
EXCEPT, if you have to be at the airport earlier, you may be before the tube, so the only option then is taxi to Paddington and Heathrow Express.

I would taxi to Paddington, then take Heathrow Express. Your taxi ride will not be much that time of day on a Saturday as you won't be slowed down by heavy traffic, and tickets for HE are much less expensive if you book them online 30 days in advance. Even that time of day, managing luggage on the tube is not a picnic.

I'd go for the car hire option. You'll be picked up at the hotel, the driver will handle the luggage, and you will be dropped at the entrance of the correct terminal at Heathrow. I'd plan on an hour for the trip, but it might take a bit less.

The Tube is certainly cheaper, takes about the same amount of time, and adds the luggage hassle.

Cabbing to Paddington, then Heathrow Express, then getting from the subterranean caves where you'd leave the train up to boarding will, I'd guess, take something like an hour, as well.

We always book a hotel at LHR the night before our flight back to the US. We enjoy the city, have a fine farewell dinner, then take the Heathrow Express and check in around 9-10 PM. The LHR website lists many hotels in all price ranges. All or most are serviced by the Hoppa bus to and from the terminal. We relax in our LHR hotel room and are only minutes from our departure terminal, which means no stress nor hassles trying to get to LHR in some ungodly morning hour. The Hoppa bus starts running at 0430 and buses make the rounds of the hotels every 30 minutes or so. Works for us.

The RS guides generally help advise on transportation options and there may be others on your tour with whom you can share a ride.

If it were me, I would just take the tube since your hotel is on the Piccadilly line. It will take about an hour. Check in online for your flight the day before.

My second choice would be a prebooked car service for the convenience of door to door service.

You'll be at The Washington Mayfair, so booking a hotel at Heathrow is not in the cards. Our guide did not have a group discussion about hotel to airport transfer, just gave us some blanket advice. We did not find out until too late that another tour member had a similarly timed flight at Gatwick. We could not take her as we booked a "salon" car for three. Turned out got be a Prius with a large car seat in the boot, so we barely squeezed our bags in. If you can get a third or fourth passenger, a car hire (not a black cab, way too costly) is economical. Even with two, the convenience of not having to walk to the tube/train carry luggage is hard to beat.

We have always paid for a private car hire to/from Heathrow. We have always been met right after we pick up our luggage. The return to Heathrow has always been smooth and on time.

Washington Mayfair Hotel to Green Park underground station is a 5 minutes walk. This station is on the Piccadilly line so you go direct to Heathrow. And the trains run all night Friday/ Saturday at 10 minute intervals so you can go as early as you need!

Thanks to everyone for sharing your experience and advice. We've decided to "wing it" and let our our energy level at the time determine whether we take the tube from Green Park or arrange a private cab. We leave next week to join the August 21 Villages of South England tour, followed by the one week London tour. Last night, we started talking about which tours we'll do in 2018.

Your guide will try to organize rides to the airport, train statins etc. If there enough people going at the same time s/he may group folks together to get cheaper taxi or shuttle rates. Of course you are free to pursue your own transit option.

Have a great trip.

You will have a great time! You will be walking to the Green Park underground station many times on this tour which will help make up your mind. I know it's economical, but in the rain (maybe), dark, pulling bags? I don't know. The arranged car was great and I'd do it again. He even made a coffee stop for us. Given the entire cost of your trip, it's a pittance.