Sad news, Sesame Street fans. That meanie Mitt Romney wants to cut funding for PBS, the public television network that has broadcast Big Bird and her fellow Muppets since 1970. "I like PBS, I like Big Bird," he claimed during Wednesday's presidential debate. "But I'm not going to keep on spending money on things to borrow money from China to pay for."

In the US, the threat prompted much pain and suffering. "Yo Mitt Romney," said someone purporting to be Big Bird on Twitter. "Sesame Street is brought to you today by the letters F & U!" Now another Big Bird impersonator wants to run for president in protest. They've even mocked up a version of the Obama Hope poster that replaces Barack's face with Big Bird's.

Over in Blighty, the news prompted a more confused reaction. What the dickens is PBS? Is it the same as the BBC? Well, yes and no. PBS stands for Public Broadcasting Service, and it's a bit like the BBC, in that it provides ad-free, free-to-air television to 170 million Americans, some of whom couldn't otherwise afford to watch the box. It has a focus on educational programmes such as American Experience, which explores US history; kids' shows such as Sesame Street; and investigative documentaries such as Frontline. PBS Newshour is its flagship news programme – and is seen as a more serious affair than many of its rivals – while Charlie Rose is the network's equivalent of David Frost.

Like the BBC, it does receive public funding – but there the similarities end. Only 15% of its budget is subsidised by the government; the rest is raised through private donors. In fact, the funding it receives – $444m (£276m) – is so small compared with the rest of the US budget that it makes you wonder why Romney thinks it'll pay for his proposed tax cuts.

PBS is a much less centralised operation than the BBC, too. Its programmes aren't broadcast centrally, but via 354 local affiliates. And though the chairman of the BBC Trust is chosen, at least indirectly, by government ministers, the PBS hierarchy is fairly independent.

Most significantly, while polls do suggest PBS is America's most trusted institution, the American right is even more suspicious of PBS than British rightwingers are of the BBC. "A lot of Republicans think that even things like Sesame Street have a liberal bias," says Sarah Lyall, London correspondent for the New York Times.

That's why PBS is such a frequent source of contention between Republicans and Democrats. "The BBC is also accused of bias," continues Lyall, "but it's such a part of the fabric here that the Conservatives can't really say: let's get rid of the whole thing. They can complain about left-leaning news, but they like the concept – whereas some Americans just don't like the concept at all."