What is the best museum in London for information on London Blitz. I understand the Imperial War Museum did have an exhibit but it is not there anymore.
The Museum of London Docklands has an evocative section on the Blitz. It's a fascinating museum generally, and free to enter.
There used to be a blitz "experience" type place near London Bridge but I think it's closed now.
Yes, the "Blitz Experience" bit was connected to the old London Dungeon and was closed along with it by the reconstruction of the station.
The changes at the IWM have been controversial but I suppose you can't please everyone. There are a lot fewer artefacts to see and a lot more empty space and 'interpretation' and galleries of pictures. I guess this is the modern trend for museums, but the First World War and Trench experience exhibits weren't really that old.
The Churchill War Rooms will give you some information, particularly if you listen to the interviews of the folks who worked down there. The bunker was being used during the Blitz and the stories are fascinating to me.
The London Walks presentation of Westminster at War also generally discusses conditions during the Blitz and IIRC they also show you some of the remaining damage. I did a quick search on their site and also found a walk called The Blitz that is every Thursday at 2:30. It looks really good and yes, will have to plan my next trip to be there on a Thursday!
http://www.walks.com/our-walks/the-blitz-london-turned-crimson