London Eye (Waterloo)
London Aquarium (Waterloo)
Covent Garden (eating places, shops, London Transport Museum, Street Musicians)
Natural History Museum and Science Museum (South Kensington)
Boat Trip on the Thames from Westminster Bridge
Hampton Court Palace (Suburban train from Waterloo Station)
Chessington World of Advenutes (Suburban train to CXhessington South from Waterloo Station)
All these places have websites
www.timeout.com/london
I can add The Natural History Museum to the list.
if the children come from outside London, just travelling on the tube is a great adventure.
There are loads of free activities for Children here in London. Check them out.
https://www.google.co.uk/#q=free+things+...
You do not need to spend a penny here in London to have fun with the kids.
In addition to the above link, every city council town hall here in London lay on activities for kids of all ages.
https://www.google.co.uk/#q=london+counc...
This link gets you all the borough councils here in London - you'll need visit a site and then find the kids activities section - any problems just call the town hall on the phone.
http://www.londoncouncils.gov.uk/
More free things via Youtube
https://www.youtube.com/results?search_query=free+things+to+do+for+kids+in+london
Welcome to London - Your City
Warner Bros Harry Potter Studio Tour is great! Whether you're a fan of Harry Potter or not you and the family would absolutely love it! Once in a lifetime opportunity :)
-London Zoo
-Ghost bus tour of London
-London dungeons
-Aquarium
-Loads of parks, regents park, primrose hill, Hampstead heath, coram fields loads more
-Funfairs, usually up on bank holidays and other public holidays
-Swimming, archway swimming bars is good
-Museums, the science museum is really fun for kids
-Horse riding, most farms will do it for kids
-Feeding the ducks lol!
-Cinema
-Theatre
there are many London Travel Guides at the Library or bookstore on traveling to London with children
also check out these
http://www.freelondonevents.co.uk/
http://www.londonnet.co.uk/ln/out/ent/ki...
http://www.visitlondon.com/things-to-do/...
http://www.fodors.com/news/23-things-to-do-in-london-with-kids-6667.html
http://travel.nationalgeographic.com/travel/family-trips/london-for-kids/
Zoo
Pen Club.
