Layover in London for 7 hours

Hi! The London Uderground will take you from Heathrow to Central London without changing, but it can take a while depending on the state of the service at the time. So it might be good to think of a couple of itineraries in case you have less time or energy than you think! You can buy tickets from machines in the tube station which take credit cards and cash. Not sure how it would deal with a non UK credit card so I would suggest making sure you have some change before you enter the station. It might even be worth buying something in the airport to break a banknote, but I think the machines will take notes and give you change. There may be a person in a kiosk to buy a ticket from but they are now rare and there is often a big queue for them.
I would suggest that doing the BM plus anything else is ambitious unless you know exactly what you want to see and eat fast! I would either do that and wander around Bloomsbury and Russell Square to see the architecture, bookshops, typical London squares for the rest of the time ( yes Russell Square is probably the best station) OR keep that for another time and navigate on the Tube to, say, Charing Cross so you could start at Trafalgar Square and walk down to Buckingham Palace. It's the heart of London and you would see a lot in a short time, but it may be something you have already done.
I would suggest having a look at the map of the Tube and see where it might take you easily in the time available. Hope that is helpful,

Please pay attention to the clock. You have 8.5 hours from landing to take-off. You will likely need at least 30-45 minutes to deplane and got through immigration (mid-morning!). The tube will cost you almost an hour to either Russell Square or the Embankment area (Charing Cross was suggested), and another hour back to Heathrow - and at rush hour. You will need to be entering Heathrow at least 2 hours before your take-off, and some will say allow even more time, as you will need to go through security at a crowded time.
This probably leaves you at most about 3 3/4 hours or so that you can have available.
Not saying you can't or shouldn't do this, I know we'd go nuts hanging at an airport for even 1/2 your layover. But what you plan to do has to take in to account the time available!

Have you bought the London - Paris tickets yet?

You could go into London for a couple or 3 hours then just pop over to St Pancras International station and take the Eurostar train to the centre of Paris. Before you had taken off from Heathrow you could be in your Paris hotel, no fuss no muss.

To be safe, from door opening it'll take an hour and a half to get into town, and hour to get back, and you need to be there a couple hours early. That's four and a half, leaving two point five left over.

The walk from Great Russell to Charring Cross is about a mile. It's another half-mile to Buckingham Palace. From there, it's another five minutes to Green Park, which I think is the closest station on the Piccadilly Line which goes back to the airport.

Forgetting all the walking, you can't start to see the museum in three hours unless it's just a dash-through.

What you have is a sucker trap. I use a pause like that only to go see somebody I haven't seen in years or to eat at some place I really, really like. Otherwise it's grit the teeth and camp out at the darn airport.

Pick one thing and be careful.

We had a 4.5 hr layover in London a few trips back and I thought, oh good, lots of time to relax and go through all the shops... well, the entire 4.5 hrs were taken up with getting from one plane to the next (huge airport, tons of walking/running) and with all the stuff we had to do (customs, immigration, security - I can't remember) and waiting in very long lines. That 4.5 hrs evaporated and I never had even one minute to go into even one shop. We actually ended up having to run a very long distance to our gate and just barely made it on our plane. Just sayin...

Thanks to everyone for the reality check! Think all agree that to be safe we should just stay put at a/p and not risk any unforeseen happening. We will be sleep deprived from the flight so I agree that this is not a good plan and best to stay at Heathrow. However, Nigel made an interesting point about taking Eurostar. I'm thinking we could take tube into St. Pancras, allowing 4.5 hours for deplaning, customs, tube into town and catch the Eurostar. One of my concerns is for the baggage and the other is if 4.5 hours for all of this is reasonable or just another risk factor. We have airline reservations through to Paris so our bags go w/flight, but if we pick up and carry bags through customs and then re-check them, this could work. If not, our bags would be at a/p in Paris. I can't remember how it works. Although we have plane reservations, which we won't change w/o penalty (so we'll keep), the shuttle from a/p to Paris is pretty high (79 euro) so it would only cost frequent flier miles and $35.31 more than we've already paid. Doesn't seem like a lot to get in 3 hours earlier and before plane takes off from London. Can you tell I'm dreading the long time at the airport in London?!! Thanks so much for your thoughts on this new plan, and thanks to all of you for responding to my questions.

If you booked through to Paris and don't take all the legs, the first missed one might cancel out all the others, including getting back home.

If you booked through to Paris, you won't be able to get to your checked bags in London.

Four and a half hours is enough to make the Eurostar,

Nigel's idea was excellent, but note his caveat - - which nixes the deal for you.

Grit your teeth.

Thanks, Ed. That's what I needed to know. Should have thought of the Eurostar myself, but I'll know if I ever go to Paris again. Since I was using frequent flier miles, I just didn't think about booking only through London.....could have saved some miles. Guess I'll bring a good book and settle in at Heathrow. Many, many thanks. This forum is wonderful! Kyle

Kyle, You've made a good decision to stay at Heathrow. Remember, Heathrow has tons of shops (some of the big London stores are represented) and tons of cafes, restaurants, coffee and sandwich shops. You won't be bored or go hungry!

What mileage plan are you using? Are you sure you can't just change the reservation to drop the London to Paris leg?

If you were to go the Eurostar route you would need to take all your bags into London, which would not make doing a whirlwind tour that easy either. If you can't shorten your connection with an earlier flight there are things you can visit much nearer to Heathrow than central London as an alternative to the airport. Osterley Park which is within walking distance of Osterley underground is a frequent suggestion if the weather if favourable.

Two ideas. If you are a FF on the airline you are flying, you could pay for getting into the lounge for that airline. If you are flying Business, either w/ miles or paying, you get in for free for that day. Gives you a comfortable chair, showers, nice food and drinks for free. OR, rent a day room near Heathrow. We did that several years ago when we had a 10hr layover. Hotel Hoppa bus has a loop route that goes to all the nearby hotels for a flat rate, or used to. At the time we did this, we went to the hotel, had lunch and were able to get into our room in early afternoon and slept. Nearby hotel choices are easy to find on the web.