Heathrow late arrival - getting to Paddington

I would not count on making that connection. You cannot guarantee how long passport control will take or even if your flight will land on time. I think that is a gamble.

You might make it, but I agree that it is a gamble. I've taken a flight that arrives at 10pm at least half a dozen times. On all but one occasion, I've zipped through passport control (not a lot of flights arriving after 10pm) and taken the tube into London. The last time I took that flight (last May), I was on the tube less than 40 minutes after my flight landed. If you do decide to risk it, I'd suggest that you try to sit as close to the front of the plane as possible and walk as quickly as possible to immigration without stopping. The one time I did not make it (in 2010), my flight was delayed in the States and I didn't arrive until after midnight and had to take a taxi. The taxi was pretty quick since it was so late and about 50 GBP (much less than normal). A car service at that time of night will take between 40 minutes and an hour.

I should add one more thing. Check the schedule for both the tube and the Heathrow Connect. The last Heathrow Connect usually goes a few minutes after midnight. I always check the last train for the tube, HEX and Connect so that I know what my latest option is.

If you decide to use a private car service, Just Airports would be a good choice. Paddington is in postal code W2. There is a discount for paying cash. The cash fare for a saloon (sedan) to anywhere in W2 is £32.

We have arrived late and departed very early from Heathrow and have used a car service both times. Especially on your first trip to the UK, I would advise having a car service meet you that late. No telling what snags you might encounter and the additional cost can be chalked up to giving you peace of mind rather than fretting about how to get to the hotel in a strange city late at night.
We've stayed near Paddington station on past trips and frequented Mickey's Fish Bar at 29 Norfolk Place, just two blocks from Paddington station adjacent to the hospital there. Best fish and chips in London. We were in the place a couple years ago when a very well dressed man entered and ordered takeaway, took a phone call, and conversed with a Mr. Hilton to increase the takeaway order. Paddington Hilton is adjacent to Paddington station and we think THE Hilton's were in residence.

OK, looks like it's time for plan B. Would this work? Since it's going to be so late and I'm probably going to be exhausted, what if I stayed at the Hilton at terminal 4 that first night...then, in the morning, I could take the Heathrow Express and if it's too early to check in, ask the hotel to hold my luggage...meanwhile, start sightseeing. Is getting from T3 to T4 at midnight or possibly later at all difficult? Thanks for all the input and advice!

Susan, I wouldn't stay at Heathrow. At 10:45pm it is going to be only 4:45pm Chicago time. You will still be wide awake. I'd suggest that you get into London. I think the next day you will be glad that you did. I love the daytime flight to Europe. Often, my flight has landed early. I've never experienced a really long queue at immigration the way you have when you arrive in the morning with all the other international flights. I really think it is worth it to get into London that night. You can sleep a bit late in the morning and then get going instead of having to deal with getting into London during morning when trains are crowded. I really think the two best options are: 1) Either prebook a car service and know that you will get into London at a fixed price. OR
2) Try for the Heathrow Express. If you miss that, try the Connect. If you miss that, then your backup is a more expensive taxi.

Laura, that makes sense. Thanks so much!

While you are looking at the Heathrow Connect note that their last departure from T3 is at 23:26 M-Sat and 15 minutes earlier on Sundays. From their website there is this notice: From 11th February 2013 to 5th December 2013, Heathrow Connect will be running an hourly service Monday to Thursday after 22:00.
Please note, that these services will not be calling at West Ealing or Hanwell stations. Friday and weekend services are unaffected. This is due to essential Crossrail engineering improvements being carried out by Network Rail. I agree that the last Heathrow Express is at 23:48.

Nigel, There is a later Heathrow Connect according to the schedule. However, it is listed as the "first train" of the day rather than the "last train" ... easy to miss this when looking at the schedule. Take a look at the Heathrow Connect Schedule. Notice that the very first train of the day leaves T1-T3 at 0:07.

Oh, I'm so glad I found this threat! I'm in the same situation except I'll arrive on a Friday night. I don't have a hotel booked and I haven't decided whether to stay in the airport area or go into the city. Not my first trip to London so I'm comfortable with any options. Thoughts on whether I'd make that Heathrow Connect at 0:07 am?? At least it would be worth a try, I guess, and then a taxi would be a backup. What about arriving at a hotel or B&B at that time of night?

Ooops, word should be "thread"

"What about arriving at a hotel or B&B at that time of night?" Make SURE it's OK with them before you try this. First, you have to make sure they understand you'll be arriving late, so they don't give away your room as a "no show," and second, you have to make sure someone will be on duty to check you in (at smaller places, the desk is not staffed 24 hours a day).