The museum, which is home to hundreds of teddy bears, thousands of trains, spectacular working exhibits and even a Roman gladiator's doll mascot is about to become the latest casualty of the Asian economic crisis.
Its Japanese construction company owner, the Fujita Corporation, has been told to stick to core interests and the museum was put on the market this week for pound;5 million. This includes the freehold of the Bayswater buildings as well as its collection of 7,500 toys.
Housed in two handsome mansions merged into one building, the museum consists of 17 themed galleries occupying four floors.
Its three education officers last year laid on workshops and tours for 7,500 pupils from 200 school groups. Their 90 per cent approval rating demonstrated how much they were appreciated.
Tim Saward, education officer, said: "It is a very important day out for the children when they come here and they really get the star treatment. It is a great resource for key stage 1 pupils. There really isn't anything else like it for children of that age."
The museum's most stunning exhibit is the working model of a coal mine built by a South Wales miner and his wife 90 years ago. It took them 20 years to build, has 200 working parts and was the top exhibit in the 1924 British Empire Exhibition.
The museum also boasts a fairground complete with lights, a room given over to military toys which has the atmosphere of a First World War trench, and a forest full of teddy bears.
The museum, which runs history and technology workshops for pupils, has received many letters from children who have visited, begging for it not to be closed.
How teddy got his name, Primary magazine, page 10