This is not exactly a top secret spot, but is our favourite so far of the big London museums.
The interactive area in the basement is brilliant for toddlers, during the 10 or so minutes respite you get between rampaging school groups. If I remember, I’ll go again during the first week of the Autumn term, on the basis that hopefully no schools will have had a chance to organise their outings for that week.
The pattern exhibition on the ground floor is aimed at slightly older children but is really interesting and less hectic than the basement. The highlight for us is a little booth where you can jump and dance while watching your outline dancing on a screen in front of you, making all sorts of different patterns.
Our favourite secret bit is a mezzanine gallery that runs along the side of the ground floor Energy Hall. It has lots of model trains with buttons to press to make the wheels and pistons move. They are just the right height for toddlers, the buttons easy to press, and it always seems to be deserted, no matter how crowded the main gallery is below. And the long straight stretch of carpet makes it a great place to do a bit of wobbly running.
Cost: free, as long as you don’t mind walking past the people ready to take your £5 voluntary donation.
Travel: South Kensington tube is hopeless with a buggy. There is a campaign to improve it: http://www.exhibitionroad.com/step-free We either get a bus from Victoria or leave the buggy at home.
Where to eat: Lots of nice cafes in the museum and other options nearby.