24 hour lay over in London

Which London airport are you flying into? Neither Heathrow nor Gatwick are close to major sights in London. Both have train service to London and Heathrow is also connected by the Underground (Tube). Twenty-four hours is both an achingly long layover and a terribly short time in which to see anything of London. If you're heading home from Sweden and don't have more time to spend in London, and have something specific you'd like to see/do in London, you could make it work. But you'd need to be focused. I'd assume that with such a long layover, you'd collect your checked bags on arrival in London, but your airline can tell you how that would work.

I agree with Suz. If you have a specific sight (or a few sights) in mind, you can use a 24 hour layover to see them. But if you think that by stopping over you'll "get a taste of London," I believe you will just find it frustrating and tiring. Getting from either Heathrow or Gatwick to places you want to see takes time and/or money, and then you'd have an extra night in a hotel, then getting back to the airport the next day. Lots of moving around for not much benefit. Plus, if you fly nonstop to the US from Stockholm, you can use SAS. Even in coach, the two times I've flown them they were notably nicer than other airlines (tastier food and a little more legroom than I get on other airlines in coach).

Dennis, I think it depends on the time you arrive and if you actually have something you want to see in London. You will need to allow about 2 hours after your flight to get through immigration and into London and 3.5 to 4 hours to get from London back to Heathrow in time to go through security to your flight. Personally, I'd go for a non-stop flight.

Dennis, I say go for it if you haven't been there before! I've only been to London once, last summer, and if I could have had a 24-hour layer when we went through there last month, I would have take my 13 students in to the city. Especially if it's not winter, I would say to go ahead and go down to the Thames waterfront - Southbank (south bank has London Eye, Tate Modern, the Globe Theatre, National Theatre, an auditorium, etc; north bank has Parliament Blgs, Westminster Abbey, St. Paul's Cathedral, Tower of London etc). There you will see tons of the major sites and you could pick one or two to enter. This is where I went the first evening I was in London and I loved it! Even the people-watching was amazing.There was an amazing art installation all along the waterfront, too, but that may have been just because of the Olympics. There's good tube service, including a "fast" train from Heathrow. Just ask for directions from the airport.
(I assumed this is the airport you're flying into and out of. Also remembering a beautiful warm evening, but I imagine it would still be amazing in the rain)

There are lots of hotels near (or at) Heathrow...you could take the airport hopper and take the express in if you aren't worried about cash. Um, we've been thru Heathrow a few times and to get thru immigration took anywhere from maybe 45-60min (1st trip with lines as long as the room) to...seriously...10-15 min last time - there was NO ONE around at all, I think there were maybe a few dozen people ahead of us, flying in from Canada and we arrived early morning (7am-ish) Our last trip over we flew into London (Heathrow) and were flying out to Venice (Gatwick) the next day at 1pm. We got in (flights from Nova Scotia arive early morning), made our way to our airbnb in the city (we've been here before, so weren't desperate to see everything), went to Westminister abby for a few hours, wandered around some to see 'The Gherkin' (google it), Leadenhall Mkt, over to Tower Bridge to look at the Shard and the next morning had time to go to Trafalgar Sq for an hour. I guess the big thing is when your flight arrives...

For a quicker trip thru passport control, go straight there from your plane and don't stop at the restroom/toilet until later. This will get you closer to the front of the line.