London activities with a 4 year old?

[KEG]

I am off to London this w/e with my 4 year old. Staying with my sister so accommodation not a problem but am wondering what things to do when there which will be interesting/fun, not cost a fortune and that we won't have to queue for ages for? Any ideas anyone?

The London Aquarium ? they have good deals on the price with 2 for 1 with certain train/tube tickets - think you just have to have done one journey.

The Natural History Museum / Science Museum are good fun - and free..

I'd recommend www.kidsinmuseums.org.uk/ for good solid advice on places to go with kiddies.

A completely free day

Morning, Natural History Museum, visiting the dinosaurs.
Afternoon, the basement of the Science Museum, is a giant science place for children.
Then an hour or 2 in Harrods playing with the toys.

Sometimes me and my 4 year old get the cheap megabus to London, do this then come straight home.

Its a wonderful day.

Coram's Fields is lovely, and there's a nice cafe with good coffee.

Yes, the Science Museum is brilliant. DS (4) likes the Launchpad bit. I think it's advertised for older children but there's plenty for smaller ones to fiddle with!

A walk along South Bank is fun too, there are usually some street performers and it's good for spotting landmarks. DS has got the I Spy London book and we ticked off lots on a walk down there! You could pop in to the Tate Modern for a mooch too.