The BBC's Andy Beatt finds out how to get to Sesame Street

The Children's Television Workshop, which makes the programme, calls it the happiest address in the world.

It has won more than 100 awards, including 71 Emmys and is seen in more than 140 countries, and is watched by 10m viewers in the US alone.

'Tremendous respect for the kids'

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But in 1968, show regular Bob McGrath didn't expect the show to take off in the way it did.

"We came in with a great deal of enthusiasm, but we never knew if we'd last beyond one season."

But now he knows what the secret of the show's success is.

"Tremendous respect for the kids from day one, that has never changed. The focus has been to the children. We'd never use them at their expense, or for inside jokes," he said.

More than 250 celebrities have appeared on the programme since 1968 but according to executive producer Michael Loman, each show has the same message, no matter who appears on it.

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"The writer creates the story line, which is teaching something in the show's curriculum.

"Whatever it is, they're really teaching something in terms of the educational values of the show," he said.

Now the classroom is bigger, with the show seen in 140 countries across five continents. Big Bird and the gang are even teaching children in Mandarin.

According to J Baxter Urist of International Television, which markets the show around the world, Sesame Street can only get bigger.

He said: "We seek continued expansion, we're in Russia, in Eygpt with an Arabic production, we're hoping to go into South Africa. There are untold expansion areas for us."