I would have preferred if I could download it off the BBC's Podcast web-page but unfortunately I can't. Below is the command that I use to download the BBC World Service radio programme "Top Of The Pops" to my desktop computer, thanks to the software rtmpdump.
rtmpdump.exe -r "rtmp://wsondemandflash.bbc.co.uk/ondemand/mp4:48502/worldservice/css/latest/topofthepops" -o "topofthepops.flv"
