5 nights in London with a 4 year old

I don't have any kids - but saw this link...... there may be something for a 4 year old.

Kids in London

I would look at the Natural History Museum website http://www.nhm.ac.uk/visit.html. If your child is like most 4 year olds and likes dinosaurs, there is no doubt that he/she will see dinosaurs there! The museum is free which means if your child wants to leave after 30 minutes, no problem, and you can return another day. I have found the museum email ("contact us") responses to be very helpful---I advise you to send a quick email with your child's age and ask if there are activities geared toward 4 year olds, I'm sure you'll receive a helpful response. Also, I found most museums have small snack bars/cafeterias for a quick snack/pick me up.

The other thing to consider is to go to one of the oldest toy stores in Europe: Hamely's. They have a zillion toys (5 floors+). We went at Christmas time and it was indeed very large and my kids were amazed. Warning: have a sense of how much you are willing to spend and make sure that your child understands the concept of "window shopping" with one small toy to come home with us. http://www.hamleys.com/

There is also a new gigantic Lego's toy store (with better prices on many items than Hamley's) in Leicester Square.

When we traveled with our children, we overestimated how much they would remember/absorb/enjoy and the truth was they were very easy to please. Kids don't care where they are as long as they keep to their schedule, have some run around time, and can eat when they are hungry. When they were 9, we went to Germany, and if you ask them what they remember most it is the time they each had long sticks and pretended they were knights in a big park that we went to. So I would look at google maps around your location to find parks to play in. I might even google "sandbox near....xyz" Smple things....

Enjoy!

Your four year will love The Lion King. Go for a walk through St James Park, let him/her feed the birds, squirrels and swans. Buy a couple of disposable cameras and let your child take pictures of what ever they want to. The Princess Diana's Memorial Playground at Kensington Palace would be a great place for your child to run around and play for a little while. Hampton Court has a fun maze that they might enjoy walking through with you. Take your child to the Royal Mews at Buckingham Palace so they can see the Royal horses and carriages. I would suggest maybe for example going to the Mews, then to St James Park (5 minute walk from the Mews) to let the child run and play, then another activity like The Tower or St Pauls or Westminster Abbey. Just don't try to do to much in one day.

You asked, "Is the London Zoo worthwhile?" which has not yet been answered.
Yes, the zoo is great.
After the zoo, visit Regent's Canal which is on the northern edge of the zoo. Take a boat ride on the canal to Little Venice (not far away). Your child will love this. Then the boat will turn around and bring you back.

The area near the zoo is Regent's Park, a wonderful large green space for walking and playing. The park has a huge lake, with lots of great bird-watching; herons, ducks, geese, swans, kingfishers, etc.
There are several cafes throughout the park. The Smokehouse is the best, with a wide variety of sandwiches, salads, drinks and ice cream available.

https://www.royalparks.org.uk/parks/the-regents-park
Map of Regent's Park:
https://www.royalparks.org.uk/parks/the-regents-park/map-of-regents-park
Places to eat, drink, get ice cream:
https://www.royalparks.org.uk/parks/the-regents-park/food-and-drink

For any adults interested, Abbey Road Studios is just a short walk west of Regent's Park.

Mud Chute Farm https://www.mudchute.org. Pelicans being fed at St James Park, Head to Duck Island at the east end of St James's Park Lake, near Horse Guard's Parade, to see the pelicans receive their daily fish between 2.30pm and 3pm daily. Puppet Theatre Barge in Little Venice. Walking in any of the parks, Battersea, Hyde, or Regents (after a visit to the zoo take a paddle boat). Thames River cruise. I'd also see if Aladdin the Musical is still running.

Thanks so much for your suggestions. The Regents Canal sounds fantastic as does St. James Park. Luckily, the 4 year old doesn't mind walking (he stopped riding in his stroller at 3, his choice, not ours). One of his other interests is trains, so I'm hoping that traveling via the underground won't lose it's magic. Also, thanks for the tip about the Lego store. My wife is a huge Lego nerd, so that one's for her! From London we'll be heading to Disneyland Paris via the Eurostar for a few days. I'm not sure what the 4 year old's memories of this trip will be, but I'm sure they'll be great for his parents!