Nothing to do with teaching history in classrooms – and certainly not at KS3, but perhaps snippets could be used at KS5 – but I've got to say how fantastic the BBC radio series on the history of thought "In our time" has been recently.
A couple of weeks ago there was a brilliant programme on something called the "Needham Question", which apparantly means "why China had been overshot by the West in science and technology, despite its earlier success". More recently there was a lively and entertaining debate on Alexander Pope, in which I learned alot.
There is a podcast, but the files only remain up for a week after broadcast. If you miss this deadline though there's also a complete "real-media" archive of the show. Take a look – you won't regret it!